Robert Petitclerc

Myocardial bridging and milking effect of the left anterior descending coronary artery: Normal variant or obstruction?

Of 5,250 patients undergoing coronary arteriography over a 5 year period, 27 (0.51 percent) had an intramyocardial segment of the left anterior descending coronary artery producing a milking effect or constriction of the artery during systole. Of these, 11 patients with otherwise normal coronary arteries were studied. Hemodynamic data, coronary sinus blood flow and myocardial lactate extraction were measured during atrial pacing at rates of 120 and 150 beats/min and during a 60 watt supine ergocycle exercise test. The degree of narrowing of the left anterior descending coronary artery during systole was graded 3 (greater than 75 percent), 5 patients; 2 (50 to 75 percent), 4 patients; and 1 (less than 50 percent), 2 patients. Four patients with a grade 3 milking effect had S-T depression in the electrocardiogram indicating anterior wall ischemia and lactate production during pacing at 149 ± 2 (mean ± standard error of the mean) beats/min. Three patients had severe angina during pacing. Two patients with a grade 2 milking effect had angina-like chest pain and electrocardiographic changes during pacing at 150 beats/min. However, lactate extraction was unchanged during pacing. Two patients with a grade 1 milking effect had no angina and no electrocardiographic or metabolic abnormalities. Coronary sinus blood flow increased significantly with pacing and ergocycle exercise in all patients (rest 118 ± 8 ml/min; pacing at 150 beats/min 219 ± 27 ml/min; ergocycle exercise 251 ± 17 ml/min) (P < 0.001). We conclude that a grade 3 milking effect observed at coronary arteriography can result in significant obstruction of the left anterior descending coronary artery with typical angina and anterior wall ischemia during tachycardia. Surgical periarterial muscle resection or bypass of the left anterior descending coronary artery might be considered in symptomatic patients with this rare anomaly.

Left main coronary artery stenosis: the influence of aortocoronary bypass surgery on survival.

SUMMARYA retrospective study was carried out in 114 unoperated and 197 operated patients having left main coronary artery (LMCA) stenosis 2 50%. Including the operative mortality of 9.1%, survival at seven years was significantly greater following pure aortocoronary bypass graft surgery, 77.5% as compared to 48.5% for the unoperated patients (P < 0.01). The surgical mortality was significantly less during the last five years (1972-1976), 6.2% as compared to 17% during 1969-1971 (P < 0.025). The three year survival in patients operated since 1972 was 90.2% as compared to 60.4% for unoperated patients. Survival remained significantly higher in the operated patients when studied as subsets on the basis of the severity of the LMCA stenosis (< 70% as opposed to .70%), and on the extent of associated obstructive disease of major coronary arteries (0-1 versus 2-3 arteries). It was significantly higher, however, only in operated patients with associated stenosis > 70% of the right coronary artery. Survival was higher following surgery only when the ejection fraction was at least 0.45, or the left ventricular end-diastolic pressure below 20 mm Hg.

Effect of Physical Training on Treadmill Exercise Capacity, Collateral Circulation and Progression of Coronary Disease

Abstract The increased exercise capacity after physical training in patients with coronary artery disease has been attributed to improved oxygen supply to the myocardium by way of increased collateral circulation or reduction of myocardial oxygen consumption by extracardiac factors, or both. Fourteen patients aged 43 to 61 years (mean 51 years) with 50 percent or greater obstruction in one, two or three vessels (three, six and five patients, respectively) underwent 13 months of physical training. Clinical status was either stable or improved with training. Treadmill exercise capacity, as measured by oxygen consumption, increased 25 percent from 21.9 ± 4.8 (standard deviation) to 27.4 ± 4.1 ml/kg-min at heart rates of 154 ± 17 and 156 ± 12 beats/min, respectively. After training, new collateral vessels, apparently secondary to progression of the disease, were observed in 2 of 21 arteries significantly but not completely obstructed before training. These data are in contrast to those reported for trained dogs with incomplete obstruction. Coronary arterial lesions progressed in only 4 of 14 patients. Coronary arteriographic data from this laboratory do not support the hypothesis that the increased exercise capacity after training in patients with coronary disease can be attributed to the development of collateral circulation. It is possible that physical training may retard the progression of coronary artery disease.

Simultaneous Determination of Aortic Valve Area by the Gorlin Formula and by Transesophageal Echocardiography Under Different Transvalvular Flow Conditions: Evidence That Anatomic Aortic Valve Area Does Not Change With Variations in Flow in Aortic Stenosis☆

OBJECTIVES The purpose of this study was to determine the impact of changes in flow on aortic valve area (AVA) as measured by the Gorlin formula and transesophageal echocardiographic (TEE) planimetry. BACKGROUND The meaning of flow-related changes in AVA calculations using the Gorlin formula in patients with aortic stenosis remains controversial. It has been suggested that flow dependence of the calculated area could be due to a true widening of the orifice as flow increases or to a disproportionate flow dependence of the formula itself. Alternatively, anatomic AVA can be measured by direct planimetry of the valve orifice with TEE. METHODS Simultaneous measurement of the planimetered and Gorlin valve area was performed intraoperatively under different hemodynamic conditions in 11 patients. Left ventricular and ascending aortic pressures were measured simultaneously after transventricular and aortic punctures. Changes in flow were induced by dobutamine infusion. Using multiplane TEE, AVA was planimetered at the level of the leaflet tips in the short-axis view. RESULTS Overall, cardiac output, stroke volume and transvalvular volume flow rate ranged from 2.5 to 7.3 liters/min, from 43 to 86 ml and from 102 to 306 ml/min, respectively. During dobutamine infusion, cardiac-output increased by 42% and mean aortic valve gradient by 54%. When minimal flow was compared with maximal flow, the Gorlin area varied from (mean +/- SD) 0.44 +/- 0.12 to 0.60 +/- 0.14 cm2 (p < 0.005). The mean change in Gorlin area under different flow rates was 36 +/- 32%. Despite these changes, there was no significant change in the planimetered area when minimal flow was compared with maximal flow. The mean difference in planimetered area under different flow rates was 0.002 +/- 0.01 cm2 (p = 0.86). CONCLUSIONS By simultaneous determination of Gorlin formula and TEE planimetry valve areas, we showed that acute changes in transvalvular volume flow substantially altered valve area calculated by the Gorlin formula but did not result in significant alterations of the anatomic valve area in aortic stenosis. These results suggest that the flow-related variation in the Gorlin AVA is due to a disproportionate flow dependence of the formula itself and not a true change in valve area.

Successful Course After Supraarterial Myotomy for Myocardial Bridging and Milking Effect of the Left Anterior Descending Artery

We report 3 patients having a grade II milking effect of the proximal left anterior descending artery (LAD) and suffering from angina. Preoperative myocardial ischemia was demonstrated by stress ECG in all 3 and by pacing and lactates studies in 2. Surgical decompression of the systolically constricted artery has resulted in disappearance of angina, milking, and ischemia. Severe milking of the LAD is a rare entity, probably congenital in origin, capable of producing myocardial ischemia and possibly causing sudden death. More studies regarding its etiology and pathophysiology are necessary. Biopsy of the myocardium surrounding the artery could be useful.

Left ventricular size following endurance, sprint, and strength training

Left ventricular size following endurance, sprint, and strength training. Med. Sci. Sports Exercise, Vol. 14, No. 5, pp. 344-347, 1982. Left ventricular dimensions in adolescent boys were determined before and after three types of training regimens: endurance (END), N = 8, means = 16.8 yr; sprint (SPR), N = 8, means = 16.3 yr; strength (STR), N = 12, means = 18.7 yr. With training the END group significantly increased VO2max in 1 X min-1 (3.71 +/- 0.27 to 4.16 +/- 0.57, P less than 0.05) and in ml X min-1 X kg-1 (58.4 +/- 5.6 to 64.2 +/- 5.5, P less than 0.05). The SPR group increased VO2max in 1 X min-1 (3.63 +/- 0.63 to 3.98 +/- 0.78, P less than 0.05) but not in ml X min-1 X kg-1 (59.5 +/- 4.1 to 63.2 +/- 5.4) because body weight increased from 61.2 +/- 10.5 to 63.1 +/- 10.7 kg (P less than 0.05) with no change in percent body fat. The STR training group significantly improved upper body strength. Despite these specific training adaptations no significant modifications were found for interventricular and left ventricular posterior wall thickness or for left ventricular internal diameter in either training group. However, calculated left ventricular mass was slightly but significantly higher by 10% and 4% in the END and STR training groups, respectively. These small increases in calculated left ventricular mass with short-term training are probably caused by small but insignificant increases in left ventricular internal diameter secondary to a training bradycardia (END group: 76 +/- 8 to 64 +/- 1 beats X min-1) and to increased diastolic filling time rather than to true cardiac hypertrophy. Significant increases in aerobic capacity and in strength can occur without modification of left ventricular dimensions.

Nitric oxide inhalation in the treatment of primary graft failure following heart transplantation

BACKGROUND Primary graft failure from right or left ventricular insufficiency remains a serious cause of early death following heart transplantation. Inhaled nitric oxide (NO) is a potent pulmonary vasodilator that could decrease pulmonary pressure and improve right ventricular function. METHODS Two cases of early graft failure following orthotopic heart transplantation were treated with NO inhalation. The treatment consisted of inhalation of 20 ppm of NO, introduced 4 to 6 hours following transplantation, in 2 patients supported with high doses of inotropic agents and vasopressors in addition to the intra-aortic balloon pump. RESULTS In the first and second cases, NO inhalation resulted in a decrease in pulmonary artery pressure, in a decrease in pulmonary vascular resistance and in an increase in cardiac index. In the second patient, systemic oxygenation improved markedly 30 minutes after initiation of NO. In the 2 patients, NO inhalation, mechanical ventilation and the intra-aortic balloon pump were weaned 4 days following transplantation. CONCLUSION Primary graft failure from donor ischemic damage, reperfusion injury or pulmonary hypertension remains a serious complication. The use of an intra-aortic balloon pump, inotropic agents and of inhaled NO appears to offer the best support for recovery of donor heart function. Primary graft failure from right or left ventricular insufficiency remains a serious cause of early mortality following heart transplantation. Ischemic damage of donor heart, reperfusion injury or pulmonary hypertension are the main causes of early graft failure. Although the cause is multifactorial, treatment of primary organ failure remains difficult with dismal results. The objective of the present study was to review the result of 2 patients with donor right heart failure following heart transplantation treated with inhaled nitric oxide (NO).

Percutaneous mitral valvuloplasty in surgical high risk patients

Among 126 consecutive patients undergoing percutaneous mitral valvuloplasty, 34 were judged to be at high risk for surgery on the basis of age greater than 70 years (n = 13), New York Heart Association functional class IV (n = 11), ejection fraction less than or equal to 35% (n = 3), severe pulmonary hypertension (n = 7), need for associated coronary bypass (n = 4) or additional valve surgery (n = 20) or severe pulmonary disease (n = 3). Baseline features of the high risk group were substantially worse than those of the other patients: age (65 +/- 11 versus 49 +/- 12 years; p = 0.0001) and echocardiographic score (9.4 +/- 1.8 versus 8.2 +/- 1.5; p = 0.005) were higher, whereas cardiac output (2.9 +/- 0.9 versus 4.1 +/- 1.2 liters/min; p = 0.0001) and mitral valve area (0.9 +/- 0.4 versus 1.1 +/- 0.3 mm2; p = 0.002) were lower. Three high risk patients experienced technical failures and three others had major complications. Among the remaining 28 patients, 18 (65%) had a complete hemodynamic success, 4 (14%) an incomplete success and 6 (21%) hemodynamic failure. Stepwise logistic regression analysis retained echocardiographic score as the only factor independently predictive of success. The percent increase in mitral valve area also correlated with echocardiographic score (r = 0.51, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Left main stenting-as a bridge to surgery-for acute type A aortic dissection and anterior myocardial infarction.

Acute anterior wall myocardial infarction is a rare but often catastrophic presentation of ascending aortic dissection. We report the case of a patient who was successfully treated by direct stenting of the left main coronary artery, allowing for definitive surgical correction. Cathet. Cardiovasc. Intervent. 51:74–77, 2000.

Balloon mitral commissurotomy for mitral restenosis after surgical commissurotomy

Balloon mitral commissurotomy (BMC) was performed in 113 patients. Of these patients, 27 (24%) (25 women and 2 men, aged 49 +/- 13 years) had recurrent mitral stenosis 13 +/- 6 years (range 5 to 29) after surgical commissurotomy. Eleven patients (41%) were considered at high risk for surgery. BMC resulted in an increase in mitral valve area from 1.1 +/- 0.3 to 1.9 +/- 0.7 cm2 (p < 0.0001), and a decrease in mean mitral gradient from 16 +/- 7 to 6 +/- 3 mm Hg (p < 0.0001). An optimal result of BMC (increase in valve area > or = 25% with a post-BMC valve area > or = 1.5 cm2) was obtained in 18 patients (67%). The results did not differ from those observed in the 86 patients of our entire series without prior surgical commissurotomy. Patients with an optimal result of BMC had a more recent surgical commissurotomy and lesser morphologic alterations of the mitral valve than did those with a nonoptimal result. Patients with echocardiographic scores < 10 had an 80% success rate of BMC; however, this rate decreased to 29% for those with scores > or = 10. One patient (4%) died from a cerebrovascular accident. Clinical follow-up at 1 year showed persistent clinical improvement in 89% of patients with an optimal result of BMC; 72% were in New York Heart Association class I and 17% in class II.(ABSTRACT TRUNCATED AT 250 WORDS)