Robert I. Hamby

Reappraisal of the functional significance of the coronary collateral circulation.

A review of data in 465 patients with complete obstruction of either the left anterior descending or right coronary artery was undertaken to evaluate the functional role of the collateral circulation. Complete obstruction of a dominant right coronary artery was observed in 288 patients, 83 percent with distal filling and visualization of the posterior descending artery by way of collateral vessels. Complete obstruction of the left anterior descending artery was noted in 177 patients, 71 percent with filling and visualization distal to the obstruction by way of collateral vessels. Among patients with obstruction of the left anterior descending artery, there was a significantly greater frequency of congestive heart failure and cardiomegaly in those without collateral vessels than in those with collateral vessels. The former also had a significantly greater frequency of both electrocardiographic evidence of an anterior wall myocardial infarction and angiographic findings of anterior wall asynergy. The frequency of inferior myocardial infarction and inferior wall asynergy was not influenced by the presence of collateral vessels. These observations indicate that the collateral circulation plays a significant protective role in the presence of obstruction of the left anterior descending artery, which is not apparent with obstruction of the right coronary artery.

Coronary ectasia: Incidence and results of coronary bypass surgery

Abstract Coronary angiograms were performed in 1,660 patients between the ages of 27 and 84 years. Coronary ectasia was noted in 42 (2.5 per cent) patients. These 42 patients were compared with an equal number of patients with coronary artery disease, matched for age and sex. There were no significant differences in numbers of vessels involved with significant disease, coronary score, main left or left anterior descending artery disease, coronary calcification, hypertension, or abnormal glucose tolerance test in patients with or without ectasia. A family history of coronary artery disease, diabetes mellitus, and hypertension did not separate the groups, neither did serum cholesterol level. The serum level of triglyceride was higher in the coronary ectasia group (p

Clinical, Hemodynamic and Angiographic Aspects of Inferior and Anterior Myocardial Infarctions in Patients with Angina Pectoris

Abstract Clinical, hemodynamic and angiographic findings were reviewed in 82 patients with isolated inferior, 55 patients with isolated anterior and 27 with combined inferior and anterior myocardial infarction and were compared with findings in 100 patients without electrocardiographic evidence of a prior transmural myocardial infarction. All of the 264 patients were referred and evaluated because of angina pectoris and found, on selective coronary angiography, to have coronary artery disease. There was no significant difference in the ages of the patients in each group studied. A history of heart failure, audible gallops and cardiomegaly were more prevalent in the two groups with anterior infarction (isolated and combined with inferior infarction) than in the other two groups. The mean left ventricular hemodynamic measurements (end-diastolic pressure, end-diastolic volume and ejection fraction) in the groups of patients with a normal QRS or an isolated inferior myocardial infarction were not significantly different from those of patients with a normal left ventricle. Patients with isolated anterior myocardia infarction had abnormal end-diastolic pressure (68 percent), end-diastolic volume (51 percent) and ejection fraction (67 percent). Similarly, the group with multiple infarctions had abnormal hemodynamic measurements, with 81 percent having an abnormal ejection fraction. For the entire group of patients studied, an abnormal end-diastolic volume was always associated with an abnormal ejection fraction. Cardiomegaly on X-ray film was associated with an abnormal end-diastolic volume and ejection fraction. An abnormal contractile pattern (asynergy) was noted in 42 percent of the patients with a normal QRS; inferior asynergy was observed in 88 percent with inferior infarction, and anterior or apical asynergy, or both, was found in 90 percent with anterior infarction. All the patients with multiple infarctions had asynergy. The right coronary artery was significantly involved in 90 percent of the patients with inferior infarction, while all the patients with anterio infarction had significant disease of the left anterior descending artery. More than 80 percent of the patients with an infarction pattern on electrocardiogram had double or triple vessel disease, as compared with 68 percent of the patients with a normal QRS pattern. This study represents a select group of patients referred because of angina pectoris and cannot be extended to the asymptomatic patient with coronary artery disease. The observations made on these patients indicate that an anterior infarction (isolated or combined with inferior) in patients referred because of angina pectoris is accompanied by significant impairment of left ventricular function, whereas an inferior infarction (isolated), although accompanied by asynergy, is usually associated with normal hemodynamics. The electrocardiogram is not sensitive enough to predict reliably in the individual patient the extent and severity of the coronary artery disease.

Multiple coronary arteriosystemic fistulas

Abstract A 58 year old man presented with angina pectoris and no heart murmur. On selective coronary angiography, multiple coronary arteriosystemic fistulas involving all three major coronary arteries were found. This is the first such case reported. It is speculated that this vascular anomaly represents persistence of embryonic intertrabecular vessels that permit the coronary arteries to communicate with the left ventricular chamber through the Thebesian vessels.

Comparative study of the postoperative flow in the saphenous vein and internal mammary artery bypass grafts

Postoperative coronary bypass flow was evaluated in two groups of randomly selected patients with grafts to the left anterior descending artery (LAD). Saphenous vein bypass grafts were placed in 27 patients and internal mammary artery grafts in 25 patients. Postoperative flow studies were performed in both groups with roentgendensitometric methods based on the transit time of radiopaque media along the graft plus the mean graft diameter. There was no significant difference between the two groups of patients for age, duration of symptoms, or the frequency of hypertension, diabetes mellitus, prior myocardial infarction, or cardiomegaly. Intraoperative bypass flows were 75+/-27 and 77+/-24 ml. per minute for the saphenous vein group (SVG) and internal mammary artery group (IMAG), respectively. There was no significant difference in the heart rate or mean aortic pressure at the time of the roentgendensitometric flow study. The mean graft diameters were 3.0+/-0.5 and 1.9+/-0.3 mm. for the SVG and IMAG, respectively (p less than 0.001). The ratios of graft diameter to LAD diameter were 1.9+/-0.3 and 1.2+/-0.2 for the SVG and IMAG, respectively (p less than 0.001). The roentgendensitometric postoperative flows were 68+/-27 ml. per minute in the SVG and 46+/-16 ml. per minute in the IMAG (p less than 0.01). The present study indicates that flow in significantly higher in saphenous vein than in internal mammary artery bypasses and that the difference in flow may in part be explained on the basis of the graft diameter.

Effects of contrast medium on left ventricular pressure and volume with emphasis on coronary artery disease

Forty-one patients had left ventricular angiography repeated 3 minutes after an initial study in order to evaluate the effect of angiographic contrast medium on left ventricular end-diastolic pressure (EDP) and volume (EDV). Seven patients had no evidence of heart disease (normal group) and 34 patients had coronary artery disease. Single-vessel diseae was present in 10, double-vessel disease in 10, and triple-vessel disease in 14 patients. Seven other patients with radiopague epicardial clips previously attached to the left ventricle underwent cinefluorographic studies to determine end-diastolic intraclip distance at various intervals after a left ventricular angiogram. In all the groups studied there was a significant increase (p less than 0.005) in both the left ventricular EPD and EDV in the second angiographic study as compared to the first. This increase in EDV (deltaV) was similar in all groups. However, the increase in EDP (deltaP) was significantly greater (p less than 0.01) in patients with double- and triple-vessel disease as compared to the normal and single-vessel disease groups. Ejection fraction, per cent shortening of the heart axis, and contractile pattern in the normal subjects were not singnificantly different when the second angiographic study was compared to the first. In nine of 34 patients with coronary artery disease the second angiographic study demonstrated impairment in left ventricular contractile pattern not present in the first angiographic study. Cinefluorographic study demonstrated an increase in end-diastolic intraclip distance after the left ventricular angiogram. The change in intraclip distance corresponded directionally and temporally to the changes in left ventricular EDP. The present study revealed that the increase in left ventricular end-diastolic press-re associated with the injection of angiographic contrast medium can be explained by an increase in EDV and that such changes last for over 15 minutes and may be associated with alterations in the contractile pattern of the left ventricle.

Percutaneous transluminal coronary angioplasty: Its potential impact on surgery for coronary artery disease

Abstract The potential impact of percutaneous transluminal coronary angioplasty on surgery for angina pectoris was evaluated in 500 consecutive patients referred because of intractable symptoms. A positive lesion, that is, one appropriate for percutaneous transluminal coronary angioplasty, was defined as proximal, discrete, segmental, subtotal, noncalcific and stenotic. Significant disease was observed in 1,079 major coronary arteries, of which 9.4 percent were not appropriate for bypass surgery. Positive lesions were observed in 115 arteries (10.7 percent); these were in the left anterior descending artery in 60; in the right coronary artery in 37 and in the left circumflex artery in 18 cases. Main left coronary artery disease was present in 31 patients with six lesions appropriate for coronary angioplasty. Of these six patients none had isolated left main coronary artery disease. Operable coronary lesions were noted in 474 patients of whom 105 (22 percent) had positive lesions appropriate for angioplasty. The age of patients with such lesions was not significantly different from that of the remaining patients. However, the duration of clinical heart disease was significantly (p

Clinical and hemodynamic aspects of single vessel coronary artery disease

Abstract Two-hundred consecutive patients with arteriosclerotic heart disease underwent complete clinical and hemodynamic evaluation. Fifty-two patients (26 per cent) had significant single vessel coronary artery disease and were compared to 148 patients with more extensive coronary artery disease and to a group of 14 normal patients. The single vessel disease group, when compared to the diffuse disease group, was characterized by a shorter duration of angina pectoris, lower frequency of a history of congestive heart failure or cardiomegaly, and a lower frequency of electrocardiographic (ECG) evidence of a transmural myocardial infarction. The combination of angina pectoris for three or more years with cardiomegaly was the only factor which completely separated the two coronary disease groups. Cardiomegaly, when present in single vessel involvement, was always due to left anterior descending (LAD) disease, together with an anterior infarction on ECG and left ventricular asynergy. The single vessel disease group included 32 patients with LAD disease, 17 with RCA, and 3 with circumflex artery involvement. Resting hemodynamics in these 52 patients (other than a higher left ventricular end-diastolic pressure and wall stress) were not significantly different from hemodynamics in a normal group. Patients with diffuse disease were characterized by many hemodynamic alterations and by left ventricular (LV) asynergy, when compared to the single vessel disease or normal groups. The diffuse disease group had a lower ejection fraction (EF) and an increased frequency of LV asynergy and coronary collateral circulation than did the LAD group. In the single vessel disease group LV asynergy did not correlate with the ECG. LV synergy, however, was not found in any patient in the LAD group with abnormal Q waves on ECG. The single vessel disease group included only five patients with increased end-diastolic volume (EDV) and all had LAD involvement, increased LV end-diastolic pressure, and decreased EF. The remaining 47 patients with normal LV-EDV revealed that the LAD group had abnormal pressure-volume relationships, indicating a decreased compliance of the left ventricle.

Results of aortocoronary bypass grafting in patients with subendocardial infarction: Late follow-Up

Twenty-eight patients with subendocardial infarction (Group A) were compared with 28 patients with unstable angina (Group B) and 28 with stable angina (Group C) matched for age and sex. The three groups did not differ in prevalence of diabetes, hypertension, old infarction or duration of disease. There were no significant differences in number of diseased vessels, coronary score, abnormal left ventricular wall motion or left ventricular end-diastolic pressure. Angiograms performed 2 weeks postoperatively revealed closure of 3 of 31 grafts (16 patients) in Group A, closure of 3 of 34 grafts (17 patients) in Group B and closure of 6 of 50 grafts (22 patients) in Group C (differences not significant). Postoperative angiograms showed improved wall motion in 37 percent of Group A, 53 percent of Group B and 36 percent of Group C (differences not significant). Postoperative new Q waves appeared in one hospital in Group A and in two patients in Groups B and C. There were no hospital or late deaths. In a mean follow-up period of 29 months, 68 percent of patients in Group A, 61 percent in Group B and 54 percent in Group C were asymptomatic. Thus, bypass grafting was performed with similarly low mortality and morbidity in patients with subendocardial infarction and in those with angina; more than one third of postoperative angiograms in the three groups showed improved wall motion; and late follow-up studies demonstrated functional improvement in the majority of patients in all three groups.

Angina pectoris and intermittent claudication

Summary Sixty patients referred for angina pectoris and having coexisting intermittent claudication (Group III) were compared with two groups of patients matched for both age and sex. One group (Group I), had no evidence of either coronary or peripheral vascular disease, while Group II had only symptomatic coronary artery disease. The ages of the patients ranged from 37 to 75 years with 80 per cent of the patients 50 years or over. In group III, intermittent claudication preceded the development of angina pectoris in 41 patients (68 per cent) and with the onset of exertional angina pectoris, the intermittent claudication usually caused no major disability. The frequency of hypertension and cigarette smoking was not different when all three groups were compared. Diabetes mellitus was significantly higher in both Group II (p