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Surgical repair of stenotic ostial lesions of the left main coronary artery
J THORAC CARDIOVASC SURG 1989;98:33-6
Surgical repair of stenotic ostial lesions of the left main coronary artery Fourteen patients with isolated stenosis of the left coronary artery ostium underwent vein patch angioplasty. An anterior approach between the aorta and pulmonary artery to expose the left main coronary ostium was used in 12 of 14 patients. There were no deaths, and postoperative angiograms in 13 of the patients showed normal coronary ostial contour with normal runoff. Two perioperative myocardial infarctions were observed. Four of the 14 patients underwent an urgent operation. Isolated coronary ostial stenosis appears to be a distinct clinical entity occurring in younger patients, mostly female, and often with a short clinical course. Unstable pain and hemodynamics are observed. The common pathologic cause of the stenotic lesion is not clear.
John A. Sullivan, MD, FRCSC, and David A. Murphy, MD, FRCSC, Halifax. Nova Scotia. Canada
Stenotic lesions located at the ostium of the left main coronary artery associated with normal or small distal coronary arteries are an unusual cause of angina. In the surgical treatment, most surgeons would prefer vein or internal mammary artery bypass to one or both branches of the left system. Direct vein patch angioplasty of this lesion has been advocated for this condition. I This report describes surgical experience with 14 patients in whom repair of ostial stenosis by vein patch angioplasty was done by a different surgical approach. Methods and patients Fourteen patients have undergone plastic repair of the left main ostium between November 1983 and October 1988, within a coronary revascularization population of approximately 2800 patients. One other patient had an attempted repair, which was abandoned because of aortic root calcification,and is not included in this series. One patient included in this series underwent ostioplasty. but the diagnosis of ostial stenosis was not confirmed at operation. There were nine womenand five men with a mean age of 50 years (range 32 to 65 years). Only one patient did not have angina, having only shortness of breath. Ten patients were classified as having New York Heart Association class III disability and four, class
Fig. I. Base of left main coronary artery is exposed between aorta and main pulmonary artery. Aorta is then opened transversely, the incision extending toward ostium of left main coronary artery.
From The Maritime Heart Center. Victoria General Hospital, Halifax, Nova Scotia, Canada. Received for publication Feb. 25. 1988. Accepted for publication Nov. 30. 1988. Address for reprints: David A, Murphy, MD, FRCSC, Division of Cardiovascular Surgery. Room 3067 Dickson Center, Victoria General Hospital, Halifax. Nova Scotia. Canada B3H 2Y9.
IV disability. A strong family history of coronary artery disease was present in 12 patients, smoking history in eight, and an abnormal lipid profile in two patients. Although most patients had stable symptoms, several (four) had extremely brittle hemodynamics in the perioperative period. Two were transferred immediately from the catheterization laboratory to the operating room because of hypotension. One patient had a
33
The Journal of Thoracic and Cardiovascular
34 Sullivan and Murphy
Fig. 2. After being probed, left main coronary artery opened anteriorly for approximately I em.
Surgery
IS
cardiac arrest several hours after her catheterization and another required internal cardiac massage after induction of anesthesia. Surgical technique. The first two patients underwent the operative technique described by Hitchcock, Robles de Medina, and Jarnbroes,' in which the aorta is opened in a spiral fashion from left to right, as one would expose the aortic valve for replacement. The incision is not carried into the sinus of the noncoronary cusp, but is extended across the top of the commisure of the noncoronary cusp and left coronary cusp. The incision is then carried out the posterior wall of the left main coronary artery. In the second patient in which this was done, there was bleeding along the left main suture line, which necessitated the reinstitution of cardiopulmonary bypass. To visualize this area and gain control, we exposed the left main coronary artery by dissecting between the pulmonary artery and the root of the aorta, a procedure which gave excellent exposure and subsequent control of the bleeding. The remaining 12 patients have now undergone the following technique: A Swan-Ganz catheter (Baxter Healthcare Corporation, Bentley Laboratories, Inc., Irvine, Calif.) and an arterial line are inserted with the use of local anesthesia in the operating theater, with the cardiopulmonary bypass circuit primed. Cardiopulmonary bypass, distal ascending aortic cannulation, and either single or double venous cannulation with core cooling to 25° C are used. During the cooling period, the area between the ascending aorta and pulmonary artery is dissected cleanly with cautery. The epicardial fat over the root of the aorta is dissected to allow exposure of the junction of the right ventricular infundibular muscle with the aorta. The base of the left main coronary artery is also dissected. This dissection can be facilitated by direct palpation of the base of the artery, once preliminary dissection has been done (Fig. I). Left ventricular decompression through the top of the left atrium, in the transverse sinus, or through the right superior pulmonary vein is used, since any effluent from the left ventricular cavity during repair of the left main coronary artery easily obscures the field. After aortic crossclamping and
Fig. 3. Opened tapered vein patch is sutured into opened artery with 7-0 monofilament suture. Redundant vein can be trimmed and gradually included in aortic suture line closure.
administration of cardioplegic solution and topical ice, the aorta is opened transversely anteriorly, and the ostium of the left main coronary artery can be identified and probed. At this juncture it is important to open the loose adventitia of the aorta, adjacent to the left main coronary artery, and expose the transverse sinus. This will allow any topical ice or blood to fall away from the suture line. The left main coronary artery is opened for approximately I em beyond the lesion (Fig. 2) and a spatulated pointed patch of vein is then sutured into the opened artery with a running 7-0 monofilament suture (Fig. 3). We have found it useful to leave a length of vein intact to facilitate handling of the vein patch. Once the aortic wall is reached, the 7-0 suture is converted to 5-0 and the vein is tapered. Any excess vein can be included in the completed aortic suture line, which is done with a 4-0 horizontal mattress suture, followed with a continuous stitch.
Results One patient died of bone cancer 5 years after the operation, but she was free of angina. The remaining patients continue to be well, without cardiac symptoms, 2 months to 5 years after the operation. As part of the study protocol, all patients except one underwent repeat angiography before hospital discharge. All angiograms have shown satisfactory angiographic geometry of the ostial area. Only one patient required an additional coronary operation for right ostial disease. This did not appear amenable to vein patch ostioplasty, and a short aorta--eoronary artery vein bypass was performed. Complications. One patient had intraoperative bleeding from the suture line, necessitating reinstitution of bypass. Control was achieved by the technique described.
Volume 98 Number 1
Stenosis of coronary artery ostium
July 1989
35
Table I AIW
Date of operation
(yr)
Sex
Symptoms
32
M
Class III angina
11/83
55 49
F M
8/84 11/84
Preop. arrest
7 days
4
42
F
1/85
Preop. arrest
9 days
5 6
48 57
F F
7 8
49 36
F F
Class III angina Class IV angina. hypotension Shortness of breath. hypotension Class III angina Class IV angina. pulmonary edema Class II I angina Class III angina
9
55
M
Class III angina
3/86
9 days
10
42
F
Class II I angina
6/87
8 days
II 12 13 14
54 59 65 44
F M M F
Class Class Class Class
Case No.
2
IV III III III
angina angina angina angina
Complications
9 mos.
10 days 19 days
2/85 6/85 6/85 1/86
11/87 11/87 6/87 10/88
Recath. 10 mo
Periop. MI
Preop.IABP
7 days 3 mo
7 days Refused study 23 days 7 days
Follow-up No pain, antiplatelet drugs No pain. no drugs Occasional palpitations, no drugs No pain. no drugs CA bone, died 7/88 No pain, no drugs No pain, diazepam No pain/antiplatelet and anti hypertension drugs No pain, nifedipine and propranolol for hypertension No pain. propranolol for hypertension No pain, no drugs No pain, no drugs No pain, no drugs No pain, no drugs
\11. Myocardial infarction; IASP. intraaortic balloon pumping; CA. carcinoma.
Two patients had evidence of perioperative myocardial infarction. In one of these patients, visceral chest pain developed in the catheterization laboratory, necessitating the insertion of an intraaortic balloon and an emergency operation. There was no postoperative evidenceof wall motion abnormality or new Q waves on the electrocardiogram, but new ST depression and enzyme changes were compatible with this diagnosis. The other patient, at operation, did not appear to have ostial stenosis. The ostium accepted a 2.5 mm probe with ease. Preoperatively, at catheterization, the patient had pressure damping across the ostium and angiographic narrowing was apparent. The patient had an inferior myocardial infarction. Although subsequent angiograms and ergotamine stimulation did not prove coronary artery spasm, her anginal symptoms have been attributed to this cause. She is receiving calcium channel blockers and is without pain. Spasm played a significant role in three patients. In one patient who had a wide open vein patch ostioplasty, normal distal arteries became hypotensive with ST elevation approximately 2 hours after the operation. Despite large doses of intravenous nitroglycerin and inotropic agents, he required a thoracotomy to explore the mediastinum. The heart was enlarged and the left ventricle was poorly contracting. Large doses of intravenous nitroglycerin provided gradual improvement. His subsequent course was uneventful, and angiograms showed a wide open ostium.
One woman with class IV symptoms, who required intra aortic balloon support in the catheterization laboratory, continued to have intermittent episodes of ST elevation after cessation of bypass and required continued use of intravenous nitroglycerin and balloon counterpulsation for a further 24 hours. Pathology. In all patients, the narrowing appeared to be due to a concentric narrowing and thickening of the aorta, which did not extend along the normal-appearing main coronary artery. In most patients, the ostium barely accepted a 1.5 probe, but the distal artery was considerably larger. Although the wall thickening appears grossly to be due to yellow subintimal early atheromatous change, in none was it calcified, plaquelike, or amenable to endarterectomy. One patient had a small biopsy of the ostial tissue, which demonstrated findings compatible with fibromuscular dysplasia and no atheroma. Biopsy was not done in the other patients because it was difficult to remove even a small piece of this tissue for study without compromising the repair. Follow-up. All patients have been followed up since the operation (2 months to 5 years) (Table I). One patient has died of osteogenic sarcoma. All patients are free of cardiac symptoms. Several are receiving medications for blood pressure control. Discussion Anatomic exposure of the left main coronary artery is rarely done by surgeons unless for technical problems or
36
The Journal of Thoracic and Cardiovascular
Sullivan and Murphy
in the repair of certain congenital lesions. Left main coronary artery stenosis, including ostial lesions, conventionally is treated by standard revascularization techniques. This would include bilateral internal mammary arteries inserted to the left system or a combination of vein graft and internal mammary artery, depending on the dominance of the right system. This series of patients is unique in that the stenotic lesion was isolated to the ostium, collateral circulation was not evident, and the distal vessels were normal and often small. The main reason for selecting this surgical technique for revascularization was the apparently normal and sometimes small distal coronary vessels. The technique of vein patch angioplasty would likely not be amenable to more distal left main lesions. Conventional revascularization into small-caliber coronary arteries is not as successful as into large-caliber vessels.v' The natural history ofvein patch angioplasties into other vascular systems' and in a series of patients similar to ours warranted a further trial of this technique. Restoring a normal anatomic contour with theoretically improved hemodynamics I into a normal distal vessel system in this younger group of patients appears logical. The anterior surgical approach to the left main coronary artery between the aorta and the main pulmonary artery was adopted because of the difficulty in adequate exposure of the ostial lesion through the posterior approach described by Hitchcock, Robles de Medina, and Jambroes.' The anterior approach offers a more frontal view and was technically easier for us. Nonetheless, it is technically demanding. The average aortic clamp time was 45 minutes (range 30 to 62). We have not used vein patch osteoplasty across the right coronary ostium, although this procedure has been reported." In our patient who had this lesion, the right-angled takeoff of the right coronary artery would have made it difficult to enlarge the ostium with a vein patch. The oblique takeoff of the left main coronary artery accommodates the vein patch without difficulty. We have not applied this technique to more distal left main lesions, since conventional revascularization is usually required because of other stenotic lesions, and the results from this remain good. Stenosis of the ostium of the left main coronary artery appears to be a distinct clinical entity." It appears within a younger group of patients, mostly female, and often with a short period of symptoms. Both the clinical and
Surgery
hemodynamic status can be very unstable. Four of our 14 patients had an extremely unstable clinical course. Thompson" made a similar observation in four of five patients in his report. Angiographically, as in their series, the distal coronary arteries were normal and small, with no developed collateralization. The cause remains unclear. Thompson" reported on five female patients with this condition, one of whom died. Autopsy revealed a typical atheromatous lesion at the ostium. Biopsy results in one of our patients were compatible with fibromuscular dysplasia. Difficulty in obtaining tissue for study in other patients precludes identifying a cause at this time.
Addendum Since acceptance of this manuscript, two further patients have been successfully operated on for this condition. One man, aged 45 years, underwent vein patch angioplasty of a short (I em) left main coronary artery, with extension of the patch into the main circumflex for more diffuse, but local atheromatous disease. The distal vessels were normal. One woman, aged 35 years, underwent biopsy of the ostial orifice, which showed mixed atheromatous change, with an active fibromuscular intimal hyperplasia of the ostium and coronary artery. We are grateful to Robert M. Miller, Department of Radiology, Victoria General Hospital, for performing repeat angiography on these patients. REFERENCES I. Hitchcock JF, Robles de Medina EOR, Jambroes G. Angioplasty of the left main coronary artery for isolated left main coronary artery disease. J THORAC CARDIOVASC SURG 1983;85:880-4. 2. Fisher LD, Kennedy JW, Davis KB, et al. Association of sex, physical size, and operative mortality after coronary artery bypass in the Coronary Artery Surgery Study (CASS). J THoRAc CARDIOVASC SURG 1982;84:334-41. 3. Tobin IN, Wassertheil-Smoller S, Wexler JP, et al. Sex bias in considering coronary bypass surgery. Ann Intern Med 1987;107:19-25. 4. Hertzer NR, Beven EG, O'Hara PJ, Krajewski EP. A prospective study of vein patch angioplasty during carotid endarterectomy. Ann Surg 1987;206:628-35. 5. Lea JW IV, Page DL, Hammon JW Jr. Congenital ostial stenosis of the right coronary artery repaired by vein patch angioplasty. J THORAC CARDIOVASC SURG 1986;92: 796-8. 6. Thompson R. Isolated coronary ostial stenosis in women. J Am Coll Cardiol 1986;7:997-1003.
Surgical repair of stenotic ostial lesions of the left main coronary artery Fourteen patients with isolated stenosis of the left coronary artery ostium underwent vein patch angioplasty. An anterior approach between the aorta and pulmonary artery to expose the left main coronary ostium was used in 12 of 14 patients. There were no deaths, and postoperative angiograms in 13 of the patients showed normal coronary ostial contour with normal runoff. Two perioperative myocardial infarctions were observed. Four of the 14 patients underwent an urgent operation. Isolated coronary ostial stenosis appears to be a distinct clinical entity occurring in younger patients, mostly female, and often with a short clinical course. Unstable pain and hemodynamics are observed. The common pathologic cause of the stenotic lesion is not clear.
John A. Sullivan, MD, FRCSC, and David A. Murphy, MD, FRCSC, Halifax. Nova Scotia. Canada
Stenotic lesions located at the ostium of the left main coronary artery associated with normal or small distal coronary arteries are an unusual cause of angina. In the surgical treatment, most surgeons would prefer vein or internal mammary artery bypass to one or both branches of the left system. Direct vein patch angioplasty of this lesion has been advocated for this condition. I This report describes surgical experience with 14 patients in whom repair of ostial stenosis by vein patch angioplasty was done by a different surgical approach. Methods and patients Fourteen patients have undergone plastic repair of the left main ostium between November 1983 and October 1988, within a coronary revascularization population of approximately 2800 patients. One other patient had an attempted repair, which was abandoned because of aortic root calcification,and is not included in this series. One patient included in this series underwent ostioplasty. but the diagnosis of ostial stenosis was not confirmed at operation. There were nine womenand five men with a mean age of 50 years (range 32 to 65 years). Only one patient did not have angina, having only shortness of breath. Ten patients were classified as having New York Heart Association class III disability and four, class
Fig. I. Base of left main coronary artery is exposed between aorta and main pulmonary artery. Aorta is then opened transversely, the incision extending toward ostium of left main coronary artery.
From The Maritime Heart Center. Victoria General Hospital, Halifax, Nova Scotia, Canada. Received for publication Feb. 25. 1988. Accepted for publication Nov. 30. 1988. Address for reprints: David A, Murphy, MD, FRCSC, Division of Cardiovascular Surgery. Room 3067 Dickson Center, Victoria General Hospital, Halifax. Nova Scotia. Canada B3H 2Y9.
IV disability. A strong family history of coronary artery disease was present in 12 patients, smoking history in eight, and an abnormal lipid profile in two patients. Although most patients had stable symptoms, several (four) had extremely brittle hemodynamics in the perioperative period. Two were transferred immediately from the catheterization laboratory to the operating room because of hypotension. One patient had a
33
The Journal of Thoracic and Cardiovascular
34 Sullivan and Murphy
Fig. 2. After being probed, left main coronary artery opened anteriorly for approximately I em.
Surgery
IS
cardiac arrest several hours after her catheterization and another required internal cardiac massage after induction of anesthesia. Surgical technique. The first two patients underwent the operative technique described by Hitchcock, Robles de Medina, and Jarnbroes,' in which the aorta is opened in a spiral fashion from left to right, as one would expose the aortic valve for replacement. The incision is not carried into the sinus of the noncoronary cusp, but is extended across the top of the commisure of the noncoronary cusp and left coronary cusp. The incision is then carried out the posterior wall of the left main coronary artery. In the second patient in which this was done, there was bleeding along the left main suture line, which necessitated the reinstitution of cardiopulmonary bypass. To visualize this area and gain control, we exposed the left main coronary artery by dissecting between the pulmonary artery and the root of the aorta, a procedure which gave excellent exposure and subsequent control of the bleeding. The remaining 12 patients have now undergone the following technique: A Swan-Ganz catheter (Baxter Healthcare Corporation, Bentley Laboratories, Inc., Irvine, Calif.) and an arterial line are inserted with the use of local anesthesia in the operating theater, with the cardiopulmonary bypass circuit primed. Cardiopulmonary bypass, distal ascending aortic cannulation, and either single or double venous cannulation with core cooling to 25° C are used. During the cooling period, the area between the ascending aorta and pulmonary artery is dissected cleanly with cautery. The epicardial fat over the root of the aorta is dissected to allow exposure of the junction of the right ventricular infundibular muscle with the aorta. The base of the left main coronary artery is also dissected. This dissection can be facilitated by direct palpation of the base of the artery, once preliminary dissection has been done (Fig. I). Left ventricular decompression through the top of the left atrium, in the transverse sinus, or through the right superior pulmonary vein is used, since any effluent from the left ventricular cavity during repair of the left main coronary artery easily obscures the field. After aortic crossclamping and
Fig. 3. Opened tapered vein patch is sutured into opened artery with 7-0 monofilament suture. Redundant vein can be trimmed and gradually included in aortic suture line closure.
administration of cardioplegic solution and topical ice, the aorta is opened transversely anteriorly, and the ostium of the left main coronary artery can be identified and probed. At this juncture it is important to open the loose adventitia of the aorta, adjacent to the left main coronary artery, and expose the transverse sinus. This will allow any topical ice or blood to fall away from the suture line. The left main coronary artery is opened for approximately I em beyond the lesion (Fig. 2) and a spatulated pointed patch of vein is then sutured into the opened artery with a running 7-0 monofilament suture (Fig. 3). We have found it useful to leave a length of vein intact to facilitate handling of the vein patch. Once the aortic wall is reached, the 7-0 suture is converted to 5-0 and the vein is tapered. Any excess vein can be included in the completed aortic suture line, which is done with a 4-0 horizontal mattress suture, followed with a continuous stitch.
Results One patient died of bone cancer 5 years after the operation, but she was free of angina. The remaining patients continue to be well, without cardiac symptoms, 2 months to 5 years after the operation. As part of the study protocol, all patients except one underwent repeat angiography before hospital discharge. All angiograms have shown satisfactory angiographic geometry of the ostial area. Only one patient required an additional coronary operation for right ostial disease. This did not appear amenable to vein patch ostioplasty, and a short aorta--eoronary artery vein bypass was performed. Complications. One patient had intraoperative bleeding from the suture line, necessitating reinstitution of bypass. Control was achieved by the technique described.
Volume 98 Number 1
Stenosis of coronary artery ostium
July 1989
35
Table I AIW
Date of operation
(yr)
Sex
Symptoms
32
M
Class III angina
11/83
55 49
F M
8/84 11/84
Preop. arrest
7 days
4
42
F
1/85
Preop. arrest
9 days
5 6
48 57
F F
7 8
49 36
F F
Class III angina Class IV angina. hypotension Shortness of breath. hypotension Class III angina Class IV angina. pulmonary edema Class II I angina Class III angina
9
55
M
Class III angina
3/86
9 days
10
42
F
Class II I angina
6/87
8 days
II 12 13 14
54 59 65 44
F M M F
Class Class Class Class
Case No.
2
IV III III III
angina angina angina angina
Complications
9 mos.
10 days 19 days
2/85 6/85 6/85 1/86
11/87 11/87 6/87 10/88
Recath. 10 mo
Periop. MI
Preop.IABP
7 days 3 mo
7 days Refused study 23 days 7 days
Follow-up No pain, antiplatelet drugs No pain. no drugs Occasional palpitations, no drugs No pain. no drugs CA bone, died 7/88 No pain, no drugs No pain, diazepam No pain/antiplatelet and anti hypertension drugs No pain, nifedipine and propranolol for hypertension No pain. propranolol for hypertension No pain, no drugs No pain, no drugs No pain, no drugs No pain, no drugs
\11. Myocardial infarction; IASP. intraaortic balloon pumping; CA. carcinoma.
Two patients had evidence of perioperative myocardial infarction. In one of these patients, visceral chest pain developed in the catheterization laboratory, necessitating the insertion of an intraaortic balloon and an emergency operation. There was no postoperative evidenceof wall motion abnormality or new Q waves on the electrocardiogram, but new ST depression and enzyme changes were compatible with this diagnosis. The other patient, at operation, did not appear to have ostial stenosis. The ostium accepted a 2.5 mm probe with ease. Preoperatively, at catheterization, the patient had pressure damping across the ostium and angiographic narrowing was apparent. The patient had an inferior myocardial infarction. Although subsequent angiograms and ergotamine stimulation did not prove coronary artery spasm, her anginal symptoms have been attributed to this cause. She is receiving calcium channel blockers and is without pain. Spasm played a significant role in three patients. In one patient who had a wide open vein patch ostioplasty, normal distal arteries became hypotensive with ST elevation approximately 2 hours after the operation. Despite large doses of intravenous nitroglycerin and inotropic agents, he required a thoracotomy to explore the mediastinum. The heart was enlarged and the left ventricle was poorly contracting. Large doses of intravenous nitroglycerin provided gradual improvement. His subsequent course was uneventful, and angiograms showed a wide open ostium.
One woman with class IV symptoms, who required intra aortic balloon support in the catheterization laboratory, continued to have intermittent episodes of ST elevation after cessation of bypass and required continued use of intravenous nitroglycerin and balloon counterpulsation for a further 24 hours. Pathology. In all patients, the narrowing appeared to be due to a concentric narrowing and thickening of the aorta, which did not extend along the normal-appearing main coronary artery. In most patients, the ostium barely accepted a 1.5 probe, but the distal artery was considerably larger. Although the wall thickening appears grossly to be due to yellow subintimal early atheromatous change, in none was it calcified, plaquelike, or amenable to endarterectomy. One patient had a small biopsy of the ostial tissue, which demonstrated findings compatible with fibromuscular dysplasia and no atheroma. Biopsy was not done in the other patients because it was difficult to remove even a small piece of this tissue for study without compromising the repair. Follow-up. All patients have been followed up since the operation (2 months to 5 years) (Table I). One patient has died of osteogenic sarcoma. All patients are free of cardiac symptoms. Several are receiving medications for blood pressure control. Discussion Anatomic exposure of the left main coronary artery is rarely done by surgeons unless for technical problems or
36
The Journal of Thoracic and Cardiovascular
Sullivan and Murphy
in the repair of certain congenital lesions. Left main coronary artery stenosis, including ostial lesions, conventionally is treated by standard revascularization techniques. This would include bilateral internal mammary arteries inserted to the left system or a combination of vein graft and internal mammary artery, depending on the dominance of the right system. This series of patients is unique in that the stenotic lesion was isolated to the ostium, collateral circulation was not evident, and the distal vessels were normal and often small. The main reason for selecting this surgical technique for revascularization was the apparently normal and sometimes small distal coronary vessels. The technique of vein patch angioplasty would likely not be amenable to more distal left main lesions. Conventional revascularization into small-caliber coronary arteries is not as successful as into large-caliber vessels.v' The natural history ofvein patch angioplasties into other vascular systems' and in a series of patients similar to ours warranted a further trial of this technique. Restoring a normal anatomic contour with theoretically improved hemodynamics I into a normal distal vessel system in this younger group of patients appears logical. The anterior surgical approach to the left main coronary artery between the aorta and the main pulmonary artery was adopted because of the difficulty in adequate exposure of the ostial lesion through the posterior approach described by Hitchcock, Robles de Medina, and Jambroes.' The anterior approach offers a more frontal view and was technically easier for us. Nonetheless, it is technically demanding. The average aortic clamp time was 45 minutes (range 30 to 62). We have not used vein patch osteoplasty across the right coronary ostium, although this procedure has been reported." In our patient who had this lesion, the right-angled takeoff of the right coronary artery would have made it difficult to enlarge the ostium with a vein patch. The oblique takeoff of the left main coronary artery accommodates the vein patch without difficulty. We have not applied this technique to more distal left main lesions, since conventional revascularization is usually required because of other stenotic lesions, and the results from this remain good. Stenosis of the ostium of the left main coronary artery appears to be a distinct clinical entity." It appears within a younger group of patients, mostly female, and often with a short period of symptoms. Both the clinical and
Surgery
hemodynamic status can be very unstable. Four of our 14 patients had an extremely unstable clinical course. Thompson" made a similar observation in four of five patients in his report. Angiographically, as in their series, the distal coronary arteries were normal and small, with no developed collateralization. The cause remains unclear. Thompson" reported on five female patients with this condition, one of whom died. Autopsy revealed a typical atheromatous lesion at the ostium. Biopsy results in one of our patients were compatible with fibromuscular dysplasia. Difficulty in obtaining tissue for study in other patients precludes identifying a cause at this time.
Addendum Since acceptance of this manuscript, two further patients have been successfully operated on for this condition. One man, aged 45 years, underwent vein patch angioplasty of a short (I em) left main coronary artery, with extension of the patch into the main circumflex for more diffuse, but local atheromatous disease. The distal vessels were normal. One woman, aged 35 years, underwent biopsy of the ostial orifice, which showed mixed atheromatous change, with an active fibromuscular intimal hyperplasia of the ostium and coronary artery. We are grateful to Robert M. Miller, Department of Radiology, Victoria General Hospital, for performing repeat angiography on these patients. REFERENCES I. Hitchcock JF, Robles de Medina EOR, Jambroes G. Angioplasty of the left main coronary artery for isolated left main coronary artery disease. J THORAC CARDIOVASC SURG 1983;85:880-4. 2. Fisher LD, Kennedy JW, Davis KB, et al. Association of sex, physical size, and operative mortality after coronary artery bypass in the Coronary Artery Surgery Study (CASS). J THoRAc CARDIOVASC SURG 1982;84:334-41. 3. Tobin IN, Wassertheil-Smoller S, Wexler JP, et al. Sex bias in considering coronary bypass surgery. Ann Intern Med 1987;107:19-25. 4. Hertzer NR, Beven EG, O'Hara PJ, Krajewski EP. A prospective study of vein patch angioplasty during carotid endarterectomy. Ann Surg 1987;206:628-35. 5. Lea JW IV, Page DL, Hammon JW Jr. Congenital ostial stenosis of the right coronary artery repaired by vein patch angioplasty. J THORAC CARDIOVASC SURG 1986;92: 796-8. 6. Thompson R. Isolated coronary ostial stenosis in women. J Am Coll Cardiol 1986;7:997-1003.