Anomalous coronary artery origin and bicuspid aortic valve

A patient presenting with signs and symptoms suggesting myocardial ischemia was found to have anomalous origin of his right coronary artery from the left aortic sinus of valsalva associated with a bicuspid aortic valve. Abnormal left ventricular function with anaerobic myocardial metabolism was documented in the absence of significant coronary artery disease or aortic obstruction. The possible relationship of these findings to the coronary artery anomaly and bicuspid aortic valve is considered. The necessity of identification of the origin of the coronary arteries is re-emphasized in the evaluation of patients with bicuspid aortic valves coming to cardiac catheterization. Anomalous origin of a coronary artery is a rare occurrence. The association of this anomaly with a bicuspid aortic valve has not been emphasized and the possible clinical consequences of this combination of malformations have not been described. We recently evaluated a patient with anomalous origin of right coronary artery from the left coronary ostium and a bicuspid aortic valve. A description of these findings follows.

Effects of perhexiline on coronary hemodynamic and myocardial metabolic responses to tachycardia

Coronary hemodynamic and myocardial metabolic responses before and after perhexiline administration were studied in 21 patients with coronary heart disease during pacing-induced angina pectoris. Perhexiline increased the threshold to tachycardia-induced angina pectoris in 16 of the 21 patients (HR 123 ± 3 to 134 ± 3 beats/min, P < 0.01). Anaerobic myocardial lactate extraction was reduced by –6.1 ± 6.3 to 10.7 ± 4% after perhexiline, although lactate extraction declined in four patients and ST segment depression was not significantly changed. Myocardial oxygen extraction was enhanced, 64 ± 2 to 69 ± 2% ( P < 0.05). Coronary flow as reflected by coronary sinus blood flow was not altered (165 ± 24 to 173 ± 26 cc/min) as left ventricular oxygen utilization was increased (18.9 ± 4 to 20.9 ± 4 ml/min, P < 0.05). These findings are interpreted to indicate decreased myocardial ischemia in certain patients on perhexiline.

Long-term observations in patients with angina and normal coronary arteriograms

Thirty-seven patients (mean age 42.7 years) with angina pectoris (AP), ischemic myocardial abnormalities, and normal coronary arteriograms were followed for 4.1 years (mean). Twenty patients had typical and 17 atypical AP. Ten had abnormal serum lipids, and eight had abnormal glucose tolerance tests. Rest-to-exercise hemodynamics revealed increased left ventricular (LV) end-diastolic pressure (mean 11.2 ± 2.6 mm Hg → 19.1 ± 3.6, P < 0.05), while stroke-work index increased (+29%). LV ischemia was detected by abnormal lactate extraction with atrial pacing in 10 or ≧1 mm S-T segment depression during exercise or pacing in 27 patients. After a mean follow-up period of 4.1 years, AP decreased in 80% of cases and remained stable in the other 20% of cases. One patient died suddenly, and autopsy revealed normal coronary arteries and myocardium. In the remainder, complications of ischemia, i.e. progression of symptoms, infarction, and heart failure were absent. Seven patients restudied 4.5 years (mean) later had no changes in their previously documented hemodynamic abnormalities and normal coronary arteriograms.

The fate of patients with AP and normal coronaries with ischemic LV abnormalities (ECG, metabolic, or hemodynamic) appears favorable. AP responds to nitrate and propranolol therapy. These long-term clinical observations with angiographic and hemodynamic restudies suggest a nonprogressive disorder.

Relationship of anginal symptoms to lung mechanics during myocardial ischemia

The anginal syndrome (AP) typically includes sensations of chest tightness or difficulty in breathing. Left ventricular (LV) dysfunction during myocardial ischemia incident with AP is now well documented. Since secondary alterations in lung mechanics could relate to these symptoms, we examined airway resistance (Raw), lung volume (TGV), lung compliance (C L ), and LV pressure-volume relations during pacing-induced AP.

LV end-diastolic pressure (EDP) increased suddenly with AP, (mean + 41%, p < 0.01), without change in end-diastolic volume (EDV). LV distensibility (EDV/EDP) decreased abruptly, (–37%, P < 0.01), with reduction in airway conductance (1/Raw/TGV), (–40%, P < 0.05), and C L (–27%, P < 0.05). When AP was relieved, these changes returned toward preangina levels.

Ischemia-induced LV dysfunction abruptly increases LVEDP. The resulting increased pulmonary capillary pressure effects an alteration of lung mechanics consisting of increasing Raw and reduced C L . The changes in ventilatory effort which ensue may be interpreted as chest tightness, heaviness, or constriction by the AP patient.