Citation Nr: 0305072 Decision Date: 03/18/03 Archive Date: 03/24/03 DOCKET NO. 94-05 822 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Winston- Salem, North Carolina THE ISSUE Entitlement to service connection for coronary artery disease as secondary to service-connected post-traumatic stress disorder. REPRESENTATION Appellant represented by: Sean Kendall, Attorney at Law ATTORNEY FOR THE BOARD L. H. Eskenazi, Counsel INTRODUCTION The veteran had active service from September 1967 to April 1969, and from May 1969 to March 1977. This matter comes before the Board of Veterans' Appeals (BVA or Board) on appeal from a September 1995 rating decision of the Department of Veterans Affairs (VA) Regional Office (RO) in Winston-Salem, North Carolina, which denied the benefit sought on appeal. This appeal was previously denied by the Board in a decision dated August 7, 1997. The veteran appealed that decision to the United States Court of Appeals for Veterans Claims (Court), which vacated the Board's decision in an Order dated August 6, 1998, in accordance with a Joint Motion for Remand and for Stay of Further Proceedings. The matter was returned to the Board for readjudication. On April 15, 1999, the Board issued a new decision denying the claim on appeal. The veteran appealed that decision to the Court, and in an Order dated August 29, 2000, the Court vacated the Board's April 1999 decision, and the issue was again returned to the Board for readjudication. On November 14, 2001, the Board remanded this matter back to the RO for further development, including consideration of additional evidence, and issuance of a supplemental statement of the case (SSOC). See 38 C.F.R. § 19.31 (2002); 38 C.F.R. § 20.1904(c) (2001). The requested development was completed, and the case was returned to the Board for disposition. FINDING OF FACT The probative medical evidence does not show that the veteran's coronary artery disease (CAD) was proximately due to his service-connected post-traumatic stress disorder (PTSD), or that his PTSD permanently aggravated his CAD. CONCLUSION OF LAW The veteran's CAD is not proximately due to or the result of service-connected PTSD, and was not aggravated thereby. 38 U.S.C.A. §§ 1110, 1131, 5103, 5103A, 5107 (West 1991 & Supp. 2002); 38 C.F.R. §§ 3.159, 3.303, 3.310 (2002). REASONS AND BASES FOR FINDING AND CONCLUSION This appeal arises out of the veteran's claim that he developed CAD as a result of his service-connected PTSD. As noted in the Introduction to this decision, this matter was previously denied by the Board in decisions dated August 7, 1997, and August 29, 2000. The Court vacated each of those decisions, respectively, in Orders dated April 15, 1999, and August 29, 2000. In the more recent August 2000 Order, the Court noted that for the first time on appeal to the Court, "the appellant argues that the Board had no authority to request a medical expert opinion from [a VA doctor], because such request was not made in accordance with 38 C.F.R. § 20.901, and that the only VA employee who is permitted to render such opinion ... is the Chief Medical Director of the Veteran's Health Administration (VHA)." Court Order at 2. Consequently, in addition to vacating the Board's April 1999 decision, the Court remanded several issues to the Board for merits consideration in the first instance, which pertain to the Board's authority to request medical opinions from VHA employees. The Board will address each of those issues, and then proceed with adjudication of this appeal. The Court's first issue was framed as follows: First, although the Court acknowledges that in [Winsett v. West, 11 Vet. App. 420 (1998), aff'd ___ F.3d ___, No. 99- 7039 (Federal Circuit 1999) (unpublished decision), cert.denied, 120 S.Ct. 1251 (2000)] the Court held that 38 U.S.C. § 7109 permits the Board to obtain an expert medical opinion from a VA employee, and does not require that all medical opinions be rendered from an independent source, the Court in Winsett does not appear to have dealt with which VA employees were authorized to render such opinions. See Winsett, supra; see also 38 U.S.C. § 7109. In this regard, the Court further acknowledges that, on the Winsett facts, the VA employee rendering the opinion was not the Chief Medical Director. See id. Nevertheless, the issue before the Court in Winsett did not involve the authority of any particular VA employee, only whether obtaining a VA medical opinion as opposed to an independent medical opinion was permissible. In other words, the Court acknowledged that 38 U.S.C. § 7109 permits the Board to obtain an expert medical opinion from a VA employee, but the Court questioned which VA employees are authorized to render such an opinion. The Court's second issue was as follows: Second, although section 7109 does not appear to limit who can render a medical opinion within VA ... 38 C.F.R. § 20.901 appears to permit a medical opinion from only one VA source, that being the Chief Medical Director. Finally, the third question presented by the Court was as follows: Third, although it appears that, pursuant to 38 U.S.C. § 512(a), the Secretary has delegated in 38 C.F.R. § 2.6(a) the responsibility to render expert medical opinions to the Chief Medical Director, he does not appear in that section to have assigned to the Chief Medical Director the power to further delegate such responsibility. See 38 U.S.C. § 512(a); 38 C.F.R. § 2.6(a). Accordingly, it is unclear whether VHA Directive 10-95-040 ... is an appropriate delegation of authority to issue medical opinions from the Chief Medical Director to VAMC medical doctors. In summary, the Court's questions concern: 1) which VA employees are authorized to render medical opinions under 38 U.S.C.A. § 7109; 2) whether 38 C.F.R. § 20.901 permits only the Chief Medical Director to render a medical opinion; and, 3) whether VHA Directive 10-95-040 appropriately delegates the authority to issue medical opinions to VA medical doctors. All three issues are closely related, and the Board will address the issues together. Initially, the Board notes that subsequent to the April 1999 Board decision (and prior to issuance of the Court's August 2000 Order), there were some amendments to 38 C.F.R. Part 2, which were made effective August 30, 1999. 64 Fed. Reg. 47,111 (August 30, 1999). The purpose of the amendments was to make "miscellaneous, nonsubstantive changes to various regulatory provisions by revising or adding authority citations, updating titles of positions and VA subunits, ... and making other nonsubstantive changes for the purpose of clarification." Id. The changes pertinent to this case are as follows. Sections 2.1 and 2.2 of 38 C.F.R. were redesignated as §§ 2.2 and 2.3, respectively, and a new § 2.1 was added which states that "In addition to the delegations of authority in this part, numerous delegations of authority are set forth throughout this title." 38 C.F.R. § 2.1 (2002). Moreover, the following amendments were made to 38 C.F.R. § 2.6. The introductory text of paragraph (a) replaced "Chief Medical Director" with "Under Secretary for Health." The references in paragraph (a) to "Veterans Health Services and Research Administration" were changed to "Veterans Health Administration." The references to "Deputy Chief Medical Director" in paragraph (a) were changed to "Deputy Under Secretary for Health." 64 Fed. Reg. 47,111 (August 30, 1999). Additionally, subsequent to the Court's August 2000 Order, VHA Directive 2000-049, was issued to replace VHA Directive 10-95-040, which lapsed on April 17, 2000. The purpose of VHA Directive 2000-049 was to outline the process by which VA medical centers and their physicians provide medical reviews for Board cases that require expert advisory medical opinions. The new Directive notes that the original Directive had "inadvertently lapsed" on April 17, 2000, although the parties continued operating under its terms. The new Directive was made effective on that same date, to indicate that the procedures have been continually in force. All actions taken after April 17, 2000, were ratified. See Purpose, VHA Directive 2000-049. Finally, effective July 23, 2001, there were some amendments made to 38 C.F.R. § 20.901. 66 Fed. Reg. 38,158 (July 23, 2001). Paragraph (a) of 38 C.F.R. § 20.901 was amended to read as follows: Opinion from the Veterans Health Administration. The Board may obtain a medical opinion from an appropriate health care professional in the Veterans Health Administration of the Department of Veterans Affairs on medical questions involved in the consideration of an appeal when, in its judgment, such medical expertise is needed for equitable disposition of an appeal. 38 C.F.R. § 20.901(a). According to the Supplementary Information in 66 Fed. Reg. 38,158 (July 23, 2001), this provision had always been intended to reflect that the Board may obtain medical opinions from appropriate health care professionals in VHA (Veterans Health Administration). However, there had been some confusion as to whether this provision permitted the Board to obtain a medical opinion from an individual in VHA other than the Under Secretary for Health (previously the Chief Medical Director). The amendment to 38 C.F.R. § 20.901(a) deletes references to "Chief Medical Director" and clarifies that the Board may obtain medical opinions from appropriate health care professionals in VHA. See Supplementary Information, 66 Fed. Reg. 38,158 (July 23, 2001). The Board finds that three issued posed by the Court in its August 2000 Order are adequately answered by the amendments noted above. First, the plain language of the current version of 38 C.F.R. § 20.901(a) indicates that the Board may obtain a medical opinion from an appropriate VHA health care professional in VA. Although the amendments to this regulation were not in effect at the time that the Board sought a VHA opinion in this case, the Supplementary Information in 66 Fed. Reg. 38,158 (July 23, 2001) makes it clear that 38 C.F.R. § 20.901(a) "has always been intended to reflect that the Board may obtain medical opinions from appropriate health care professionals in VHA," and that the purpose of the amendment to 38 C.F.R. § 20.901(a) was simply to clarify this point. This answers both the Court's first and second questions as to which VA employees may render medical opinions for the Board. In regard to the Court's third issue (pertaining to VHA Directive 10-95-040), as already discussed, that Directive was replaced by VHA Directive 2000-049, which essentially affirmed and reissued the content of VHA Directive 10-95-040. These Directives are consistent with the purpose of 38 C.F.R. § 20.901(a), both currently and prior to the July 2001 amendments. As noted in the Supplementary Information to in 66 Fed. Reg. 38,158 (July 23, 2001), the Board has been using VHA medical opinions under 38 C.F.R. § 20.901(a) for many years. This process has been memorialized in a VHA "Directive" since 1995. The advisory opinions from VHA physicians have been typically provided in a much more timely fashion than those obtained from non-VA physicians, and have been responsive to the questions asked by the Board. The amendments to 38 C.F.R. Part 2 and 38 C.F.R. § 20.901(a), and the issuance of VHA Directive 2000-049, support the conclusion that the Board currently has the authority to request advisory opinions from appropriate medical professionals from VHA, and that the Board had this authority in 1999, when a VHA opinion was requested in this case. Having addressed the issues presented by the Court in the August 2000 Order, the Board will now proceed with the merits of this appeal. Initially, as noted in the Introduction to this decision, this matter was remanded by the Board in November 2001 for additional development, including compliance with the Veterans Claims Assistance Act of 2000, and issuance of an SSOC. The Board has reviewed the file, and is satisfied that the requested development was completed. See Stegall v. West, 11 Vet. App. 268 (1998) (as a matter of law, a remand by the Board confers on the veteran the right to compliance with the remand orders). The Veterans Claims Assistance Act of 2000 (VCAA) was enacted during the pendency of this appeal, on November 9, 2000. Pub. L. No. 106-475, 114 Stat. 2096 (2000); 38 U.S.C.A. §§ 5103, 5103A (West Supp. 2002). Among other things, the VCAA amended 38 U.S.C.A. § 5103 to clarify VA's duty to notify claimants and their representatives of any information that is necessary to substantiate a claim for benefits. Under 38 U.S.C.A. § 5103A, the VCAA codified VA's duty to assist, and provides that VA will make reasonable efforts to assist a claimant in obtaining evidence necessary to substantiate a claim. Implementing regulations for the VCAA were subsequently enacted and made effective November 9, 2000, for the most part. See 38 C.F.R. §§ 3.102, 3.159. The intended effect of the implementing regulations was to establish clear guidelines consistent with the intent of Congress regarding the timing and scope of assistance VA will provide to claimants who file a claim for benefits. 66 Fed. Reg. 45,620 (Aug. 29, 2001). Both the VCAA statutes and the implementing regulations will be collectively referred to as "the VCAA." One of the requirements under the VCAA is that VA notify a claimant of any information or evidence that is necessary to substantiate the claim, including which portion of evidence the claimant should provide, and which portion VA will attempt to obtain. 38 U.S.C.A. § 5103; Quartuccio v. Principi, 16 Vet. App. 183, 187 (2002). A review of the claims file shows that this requirement has been met, particularly as evidenced by a letter from the RO to the veteran dated in December 2001. That letter notified the veteran of the VCAA, and provided him with a detailed list of evidence already received in support of his claim. The letter asked the veteran to inform them of any additional evidence he wanted the RO to consider regarding his appeal. The letter also requested that the veteran complete authorization forms if he wanted VA to assist him in requesting treatment records from private doctors or hospitals. In addition to the foregoing, by rating decisions dated in September 1995, a statement of the case (SOC) issued in May 1996, and numerous SSOCs in the record, the veteran was informed of the laws and regulations governing service connection, including secondary service connection. Although the Court vacated the August 1997 and April 1999 Board decisions, those decisions remain a matter of record, and were provided to the veteran. The Board's recitation of the laws and regulations pertaining to service connection in those decisions is correct, and has not changed. In short, the Board is satisfied that the veteran was put on notice as to the evidence needed to substantiate his claim, including what evidence he should supply, and what evidence VA would assist in obtaining. See 38 U.S.C.A. § 5103. VA also has a duty under the VCAA to assist claimants in obtaining evidence necessary to substantiate a claim for benefits. 38 U.S.C.A. § 5103A. Throughout this appeal, VA has assisted the veteran in obtaining relevant evidence. The record contains the veteran's service medical records, private treatment records, and VA clinical records. Two medical expert opinions were obtained in this case, which are discussed in more detail in the decision below. The veteran was offered an opportunity to appear personally at a hearing, but he declined that opportunity. As is clearly documented in the record, attempts have been made to secure all relevant records identified by the veteran, and the Board is unaware of any additional evidence that should be obtained prior to proceeding with this appeal. In short, the Board finds that the duty to assist the veteran was satisfied, and the case is ready for appellate review. 38 U.S.C.A. § 5103A. Service connection will be granted if it is shown that the veteran has a disability resulting from an injury or disease contracted in the line of duty, or for aggravation of a preexisting injury or disease in the line of duty, in active military, naval, or air service. See 38 U.S.C.A. § 1110; 38 C.F.R. § 3.303. Disability which is proximately due to or the result of a service-connected disease or injury shall be service connected. When service connection is thus established for a secondary condition, the secondary condition shall be considered a part of the original condition. 38 C.F.R. § 3.310(a). Secondary service connection includes instances in which an established service-connected disorder results in additional disability of another condition by means of aggravation. Allen v. Brown, 7 Vet. App. 439 (1995). Where the determinative issue in a service connection claim involves a medical diagnosis, competent medical evidence is required. This burden cannot be met by lay testimony because lay persons are not competent to offer medical opinions. See Espiritu v. Derwinski, 2 Vet. App. 492, 494-95 (1992). The veteran maintains that he developed CAD as a result of his service-connected PTSD. He does not contend that his CAD began in service, or is directly related to his active service. Rather, he has limited his arguments to principles of secondary service connection. As such, the Board will analyze the veteran's claim on that basis. A review of the veteran's service medical records is negative for any evidence of CAD or a cardiovascular disorder. Following service separation, a May 1977 VA examination report indicates that the veteran's cardiovascular system was normal. His blood pressure was 110/72. In January 1989, the veteran was admitted to a VA hospital with complaints of chest pain. It was noted that there was no previous history of chest pain or heart disease. The final diagnosis was acute myocardial infarction. He was discharged in early February 1989. In March 1989, the veteran was readmitted to a VA hospital with complaints of increased daily chest pain for the prior week. He was diagnosed with unstable angina, and transferred for immediate catheterization. A stress and redistribution thallium test revealed an abnormal baseline, a small area of inferoapical ischemia, and a small to moderate area of high septal ischemia. A March 1989 VA transfer summary contains a primary diagnosis of CAD, with a secondary diagnosis of hypercholesterolemia. It was noted that the veteran had a history of tobacco abuse, described as 20 packs per year. It was also noted that the veteran had a strong family history of CAD, with his father dying at age 56 from a myocardial infarction (MI), and his sister dying at age 47 from a MI. In July 1989, the veteran was admitted to a VA hospital with an admission diagnosis of unstable angina. The examiner noted that the veteran's cardiac history dated to January 1989, at which time he experienced a non-Q wave MI without complication. The examiner also noted that the veteran had a family history of tobacco use and risk factors for CAD. The discharge diagnoses included unstable angina, two vessel CAD, renal insufficiency, and tobacco abuse. A December 1989 VA hospital report indicates that the veteran presented to the Hampton VA medical center in early December, with complaints of increasing frequency of angina. The veteran was transferred to a VA hospital in Richmond for catheterization and an angioplasty. He was transferred back to the Hampton VA medical center, and the final diagnosis was CAD, status post percutaneous transluminal coronary angioplasty. A March 1991 stress and redistribution thallium revealed an abnormal baseline and a small amount of posterolateral ischemia. An August 1994 VA examination for miscellaneous neurological disorders noted a history of MI and cardiac angioplasty, but cardiovascular examination revealed regular rate and rhythm, without gallops, murmurs, or rubs. A VA outpatient treatment record dated in May 1995, reflects that the veteran was seen with complaints of increased chest pain over the last three weeks. He noted a relationship with his PTSD sessions. He also noted the same chest pain with walking. The examiner's impression was increased angina associated with increased stress. Later that same month, the veteran was seen with complaints of running a temperature, sweating, and aching all over. The assessment included CAD and PTSD. An August 1995 VA progress note reflects a diagnosis of PTSD. In August 1995, the veteran filed a claim for service connection for PTSD. In a September 1995 rating decision, service connection for PTSD was awarded, and a 10 percent disability rating was assigned. The RO denied service connection for CAD as secondary to PTSD, which the veteran appealed. A November 1995 private medical statement from Derrick E. Ridley, M.D., F.A.C.C., indicates that the veteran was admitted to Sentara Hampton General Hospital earlier that month, and diagnosed with an acute non Q-wave MI, which resolved with medication. The hospitalization records were attached. In June 1996, a handwritten, undated, letter was received from a VA staff physician at the VA medical center in Hampton. She described the veteran's cardiac history, and noted that he served in Vietnam prior to the cardiac conditions. She also noted that in 1995, he was diagnosed with PTSD based on his Vietnam service. She stated: "It is well known that stress is a critical element in the development of atherosclerotic heart disease." She opined: "It is my medical opinion that a significant part of his cardiac condition is service connected." In February 1999, the Board referred this issue for a medical expert opinion, pursuant to VHA Directive 10-95-040. 38 U.S.C.A. § 7109; 38 C.F.R. § 20.901. The Board asked the following: What is the medical etiology of the veteran's heart disease, and what is the medical likelihood that his service- connected PTSD caused or permanently worsened his heart disease? If you find that PTSD permanently worsened the heart disease, please fully describe the increment of additional heart disability which you attribute to PTSD. In March 1999, a response was received from the Chief of Cardiology at the VA medical center in New York, who indicated that he had reviewed the veteran's case, including the hospitalization reports and the reports of cardiac catheterization, and concluded that the veteran's CAD is not related to his PTSD. As reasons for his conclusion, the physician noted that the veteran has multiple risk factors for CAD, including a strong family history of CAD, as well as hypocholesterolemia and smoking. He pointed out that the veteran had an inferior wall myocardial infarction in 1989, which was six years before there was any mention of PTSD in the medical record. He opined that the "natural history of such diffuse coronary artery disease is progression of lesion severity leading to subsequent myocardial infarction and deterioration of ventricular function." He stated that the "likelihood of disease progression is increased by smoking." He further stated that "[t]his is in fact the course of this veteran's disease which is entirely explained by the known risk factors and is not likely to have been significantly altered by the development of PTSD in 1995." He concluded that "the cause of the veteran's coronary artery disease is atherosclerosis secondary to hyperlipidemia and smoking." He stated that there was "no evidence that PTSD either caused or permanently worsened the heart disease." In August 1997, VA staff physician from the VA medical center in Hampton submitted a typed statement, which is duplicative of the handwritten statement submitted in June 1996. A February 1997 VA hospitalization report reflects that the veteran underwent a dobutamine stress echocardiogram and a cardiac catheterization. The veteran's medical history was summarized, and it was noted that the veteran admitted to smoking one pack of cigarettes per day. The discharge diagnosis was non Q-wave myocardial infarction, and post myocardial infarction angina. Significant CAD was revealed on the cardiac catheterization. An April 1999 VA outpatient treatment record indicates that the veteran had PTSD, which had its onset back in 1968, and had persisted for the past 30 years. In February 2001, the veteran's representative submitted two additional medical reports in support of the veteran's claim. A January 2001 report from Craig N. Bash, M.D., a neuro- radiologist, sets forth a list of documents that he had reviewed from the veteran's claims file, including service medical records, VA medical records, and physician statements. Dr. Bash opined that the veteran's CAD/MI "was likely made worse by his longstanding PTSD ... based on [the veteran's] medical record and literature references ..." Dr. Bash indicated that he did not examine the veteran. The veteran's representative also submitted a May 1999 statement from the same VA staff physician at the VA medical center in Hampton. The statement indicated that although the veteran had three risk factors for CAD, consisting of smoking, a family history of heart disease, and hyperlipidemia, his PTSD was "a significant fourth factor in the development of his current disabling CAD, beginning in 1968." In May 2001, the Board sought an independent medical expert opinion on this issue. The Board asked the following question: What is the medical etiology of the veteran's heart disease? What is the medical likelihood that his service- connected PTSD caused or permanently worsened his heart disease (i.e., is there a cause-and-effect relationship)? If you find that PTSD permanently worsened (i.e., aggravated) the heart disease, please fully describe the increment of additional heart disability which you attribute to PTSD as opposed to other factors. In June 2001, a response was received from the Chief of Cardiology, at the University of Texas Health Science Center at San Antonio, who indicated that he had reviewed the veteran's medical records, and concluded that there was no causal relationship between the veteran's heart disease and his service-connected PTSD. He based his opinion on the fact that CAD first manifest in 1989, while there was no evidence of a psychiatric disorder until six years later, in 1995. In light of the veteran's history of cigarette smoking and a strong family history of CAD, the physician believed that "it is more likely than not that [the veteran's] heart problems occurred independently of his PTSD." The examiner indicated that there was little evidence in medical literature linking PTSD and heart disease, but even if there was such evidence, the veteran's risk factors "would make it impossible to conclude that the PTSD played any primary role, and it is more likely that his heart disease would have manifest regardless of the PTSD, even had it manifest before, not after the heart condition." A July 2001 statement from the above noted VA staff physician from the Hampton VA medical center indicates that although the veteran's PTSD was not diagnosed until 1995, it was the result of his involvement in the Vietnam war, and thus, was most likely present from 1969 onward. The examiner further stated that although the veteran had two other risk factors, his PTSD "certainly would be considered an additional etiologic agent for his exacerbation of coronary artery disease." As noted earlier in this decision, in November 2001, the Board remanded this matter back to the RO for compliance with the VCAA, and for issuance of a SSOC that considered all new evidence. The RO issued its VCAA letter in December 2001 and a SSOC in February 2002. Since the time of the Board's remand, substantial VA treatment records have been associated with the veteran's claims file from VA medical centers in Richmond and Hampton, Virginia. Those records are dated from May 1996 to March 2002, and include some copies of records already contained in the claims file. There is also an October 2002 VA examination report for PTSD. Collectively, the additional VA medical evidence reflects continued treatment for heart disease and PTSD, as well as other disabilities unrelated to the issue on appeal. However, there are no additional medical statements or evidence pertaining to a relationship between PTSD and CAD. The Board has carefully reviewed all the medical evidence in this case, but concludes that the preponderance of the evidence is against a claim for service connection for CAD as secondary to PTSD, for reasons explained below. The record indicates that the veteran's first signs of heart disease appeared in January 1989, and the first diagnosis of PTSD was in 1995. There is no showing that heart disease was present in service or for many years thereafter. There are medical opinions both for and against the veteran's claim that his CAD is proximately due to or aggravated by his service- connected PTSD. The medical opinions supporting the veteran's claim are contained in four statements from a staff physician at the VA medical center in Hampton, who examined and treated the veteran, and a statement from a private neuro-radiologist, Dr. Bash, who reviewed the veteran's file and submitted a statement upon request by the veteran's representative. The statements weighing against the veteran's claim were rendered by the Chief of Cardiology at the VA medical center in New York, and the Chief of Cardiology at the University of Texas Health Science Center. As noted above, there are four statements from the VA staff physician at the Hampton VA medical center. The first two statements (a handwritten statement received in June 1996, and a duplicative typed statement dated in August 1997) are identical in content and indicate that it is "well known" that stress is a critical element in the development of heart disease. The physician opines, "a significant part of [the veteran's] cardiac condition is service connected." The third statement, dated in May 1999, acknowledges the veteran's risk factors for CAD, including smoking, family history, and hyperlipidemia, but adds that PTSD was "a significant fourth factor" in developing CAD. The fourth statement, dated in July 2001, the physician opines that, although the veteran's PTSD was not diagnosed until 1995, it was the result of his Vietnam service and therefore was most likely present from 1969 onward and that, although other risk factors are present, PTSD certainly was "an etiologic agent for his exacerbation of CAD." Dr. Bash, in his January 2001 statement, identifies himself as a neuro-radiologist who rendered an opinion at the request of the veteran's representative. Dr. Bash concludes that the veteran's CAD/MI was "likely" made worse by his longstanding PTSD. He indicates that he reviewed the records and relied on his research into the medical literature to support his conclusion. Dr. Bash cites a medical article entitled, "Life event stress and Myocardial reinfarction: a prospective study," dated in 1994. He provides the following excerpt from this article in support of his conclusion, "[t]his three year prospective study . . . reveals significant independent associations between acute Myocardial infarction (AMI) . . . and risk of recurrent AMI and death." The other quoted study, apparently from a psychiatric or psychology journal, dated in 1981, states the "Type A behavior pattern has been associated with the onset of myocardial infarction. . ." The medical evidence weighing against the veteran's claim includes two medical expert opinions, both by Chiefs of Cardiology, one from a VA medical center and the other from an independent medical expert at a leading university, which was obtained by the Board pursuant to 38 U.S.C.A. § 7109, 38 C.F.R. § 20.901(d). The first medical expert opinion, from the Chief of Cardiology at the VAMC in New York, reflects that the physician reviewed the veteran's medical records and concluded that the veteran's CAD was caused by atherosclerosis secondary to hyperlipidemia and smoking. He found no evidence that PTSD either caused or worsened the veteran's heart disease. A second medical expert opinion, from the Chief of Cardiology at the University of Texas Health Science Center, concludes that there is no relationship between the veteran's heart disease and his PTSD. Rather, the physician attributed the veteran's heart disease to his history of cigarette smoking and his strong family history of heart disease. He stated that it was more likely that the veteran's CAD occurred independently of his PSTD. The Board's responsibility is to assess the credibility and weight given to the evidence. See Guerrieri v. Brown, 4 Vet. App. 467, 470-471 (1993) (the probative value of medical evidence is based on the physician's knowledge and skill in analyzing the data, and the medical conclusion the physician reaches; as is true of any evidence, the credibility and weight to be attached to medical opinions are within the province of the Board). The Board may also rely on a particular medical expert's opinion as satisfying the statutory requirement of an adequate statement of reasons or bases where the expert has given fair consideration to the material evidence that appears to support the appellant's contentions. Wray v. Brown, 7 Vet. App. 488, 492-93 (1995). In reaching the determination in this case, the Board finds that the opinions from the two Chiefs of Cardiology are be more probative than the opinions provided by the VA staff physician and the private neuro-radiologist. They are accorded more weight for several reasons. First, it is noted that they answered the specific questions posed to them and supported their opinions by clinical findings in the record. It is also apparent that each doctor reviewed the veteran's medical history before reaching his conclusions. For example, the Chief of Cardiology from the VA medical center in New York discussed the history of the veteran's heart disease, and commented on the progression of heart disease, including the increased effects of such progression when combined with risk factors such as smoking. Similarly, the Chief of Cardiology at the University of Texas Health Science Center discussed the veteran's medical history, as well as medical literature, in reaching his conclusion. Second, both are specialists in the field of cardiology, and as Chiefs of Cardiology, have oversight responsibility over the cardiology departments at major hospitals. We believe that physicians with this degree of expertise and responsibility are more likely to be well informed as to the state of medical knowledge regarding whether there is a relationship between PTSD and the development or aggravation of heart disease and have a high degree of expertise in evaluating the particular facts of this case from their review of the record. Neither the VA treating physician nor the private neuro-radiologist is shown to have similar specialized expertise in the relevant field of medicine. Third, the two cardiologists' opinions are mutually consistent in attributing the veteran's CAD to risk factors such as smoking, strong family history of heart disease and hyperlipidemia and in concluding that the veteran's PTSD played no significant role in the development of CAD. Each point out that the veteran's heart disease was medically diagnosed years before there was any indication that the veteran had PTSD. Moreover, the cardiologist's opinions are consistent with those of the VA staff physician and the private neuro-radiologist to the extent that all recognize that factors other than PTSD played a role in causing or exacerbating the veteran's heart disease. In contrast, we find the statements from the VA staff physician and the private neuro-radiologist to be less than persuasive. In her first two statements, the VA staff physician's stated reason for attributing the veteran's heart disease to service is simply that it is "well known" that stress contributes to cause heart disease. These statements offer a bare conclusion as to proximate causation and make no mention of the other risk factors present in this case for the development of CAD. The third statement acknowledges the risk factors noted by the two cardiologists, but again asserts, without explanation, that PTSD was another factor in the development of the veteran's heart disease. Although the VA staff physician has indicated in her third and fourth statements that the veteran's PTSD was present since service, this is unsubstantiated by the evidence of record, which does not establish the presence of PTSD prior to 1995. Moreover, in her fourth statement, the physician opines that PTSD exacerbated the veteran's CAD, in contrast to her earlier statements indicate that she believed that the psychiatric disorder was a factor in causing the heart disease. While we have given careful consideration to the neuro- radiologist's opinion, we note that the medical literature that he refers to and apparently relied upon in formulating his opinion are articles published in 1994 and 1981, as well as a 1997 cardiology text. He states both that the veteran's heart disease was "made worse" by his PTSD and that the PTSD "contributed directly to his CAD/MI." As noted above, we conclude the two Chiefs of Cardiology are more likely to be better informed than a neuro-radiologist as to the current state of medical knowledge regarding whether there is a relationship between PTSD and the development or aggravation of heart disease and have a higher degree of expertise in evaluating the particular facts of this case from their review of the record. We also note that both cardiologists expressed essentially similar opinions and that one of these cardiologists, unlike Dr. Bash, is an independent medical expert. The Board acknowledges the veteran's statements wherein he maintains that the stress and symptoms attributable to his service-connected PTSD contributed to his CAD. However, as a layperson with no apparent medical expertise or training, the veteran is not competent to provide a medical diagnosis or an opinion as to medical causation. See Espiritu, 2 Vet. App. at 494-95 (laypersons may be competent to provide an "eye- witness account of a veteran's visible symptoms," but they are not capable of offering evidence that requires medical knowledge). Rather, medical evidence on this point is needed. In the present case, there is probative medical evidence indicating that the veteran's CAD developed independently of his service-connected PTSD. As explained above, despite the evidence supporting the veteran's claim, the Board is more persuaded by the opinions provided by the Chiefs of Cardiology, and as such, the evidence does not support the veteran's claim for service connection. Accordingly, the Board finds that the preponderance of the evidence is against a finding that CAD is proximately due to service-connected PTSD. As to this material issue, the record does not present an approximate balance of positive and negative evidence regarding the merits of the veteran's claim that would give rise to a reasonable doubt in favor of the veteran. Thus, the provisions of 38 U.S.C.A. § 5107(b) are inapplicable, and the appeal is denied. See Ferguson v. Principi, 273 F.3d 1072 (Fed. Cir. 2001) (38 U.S.C.A. § 5107(b) only requires that the Board consider all the evidence and material of record; the benefit-of-the-doubt provision only applies where there is an approximate balance of positive and negative evidence). ORDER Service connection for CAD, as secondary to service-connected PTSD, is denied. STEVEN L. KELLER Member, Board of Veterans' Appeals IMPORTANT NOTICE: We have attached a VA Form 4597 that tells you what steps you can take if you disagree with our decision. We are in the process of updating the form to reflect changes in the law effective on December 27, 2001. See the Veterans Education and Benefits Expansion Act of 2001, Pub. L. No. 107-103, 115 Stat. 976 (2001). In the meanwhile, please note these important corrections to the advice in the form: ? These changes apply to the section entitled "Appeal to the United States Court of Appeals for Veterans Claims." (1) A "Notice of Disagreement filed on or after November 18, 1988" is no longer required to appeal to the Court. (2) You are no longer required to file a copy of your Notice of Appeal with VA's General Counsel. ? In the section entitled "Representation before VA," filing a "Notice of Disagreement with respect to the claim on or after November 18, 1988" is no longer a condition for an attorney-at-law or a VA accredited agent to charge you a fee for representing you.