Donald B. Doty

Does Visual Interpretation of the Coronary Arteriogram Predict the Physiologic Importance of a Coronary Stenosis

To assess visual interpretation of the coronary arteriogram as a means of predicting the physiologic effects of coronary obstructions in human beings, we compared caliper measurements of the degree of coronary stenosis with the reactive hyperemic response of coronary flow velocity studied with a Doppler technique at operation, after 20 seconds of coronary arterial occlusion. In 39 patients (44 vessels) with isolated, discrete coronary lesions varying in severity from 10 to 95 per cent stenosis, measurement of the percentage of stenosis from coronary angiograms was not significantly correlated (r = -0.25) with the reactive hyperemic response. Results were the same for obstructions in the left anterior descending, diagonal, and right coronary arteries. Underestimation of lesion severity occurred in 95 per cent of vessels with greater than 60 per cent stenosis of the diameter by arteriography. Both overestimation and underestimation of lesions with less than 60 per cent stenosis were common. These results, together with the high interobserver and intraobserver variability of standard visual analysis of angiograms, suggest that the physiologic effects of the majority of coronary obstructions cannot be determined accurately by conventional angiographic approaches. The need for improved analytical methods for the physiologic assessment of angiographically detected coronary obstructions is apparent.

Decreased coronary reserve: a mechanism for angina pectoris in patients with aortic stenosis and normal coronary arteries.

The pathogenesis of angina pectoris in patients with aortic stenosis and normal coronary arteries remains uncertain. Using a specially designed Doppler probe, we measured the maximal velocity of coronary blood flow in the left-anterior descending coronary artery at the time of elective open-heart surgery in 14 patients with aortic stenosis and left ventricular hypertrophy (13 had angina) and in 8 controls without left ventricular hypertrophy. The ratio peak velocity of coronary blood flow, after a 20-second occlusion, to resting velocity was decreased by more than 50 per cent (P less than 0.05) in the patients with aortic stenosis. In 7 of the patients this ratio was decreased by more than 75 per cent. Studies of the velocity of coronary blood flow in vessels perfusing the right ventricle in these patients showed only mild abnormalities. These data demonstrate a selective and marked decrease in coronary reserve to the hypertrophied left ventricle in patients with severe aortic stenosis. The impairment in coronary reserve is probably an important contributor to the pathogenesis of angina pectoris in these patients.

The value of lesion cross-sectional area determined by quantitative coronary angiography in assessing the physiologic significance of proximal left anterior descending coronary arterial stenoses.

The results of previous work from this laboratory have shown a poor correlation between percent stenosis (determined visually with calipers) and the coronary reactive hyperemic response (an index of maximal coronary vasodilator capacity) determined during cardiac surgery. This study was performed to determine whether other parameters of lesion severity could predict the reactive hyperemic response and thus the hemodynamic significance of coronary stenoses in human beings. Twenty-three patients with lesions in the proximal left anterior descending coronary artery were studied. To account for differences in expected vessel size, patients with large diagonal branches (greater than one-half the diameter of the left anterior descending artery) arising before the lesion were excluded. Computer-assisted quantitative coronary angiography was used to measure percent diameter stenosis, percent area stenosis, and minimal stenosis cross-sectional area. With a pulsed Doppler velocity probe, reactive hyperemic responses were recorded after a 20 sec coronary occlusion of the left anterior descending artery at cardiac surgery before cardiopulmonary bypass and were quantified by the peak/resting velocity ratio (normal greater than 3.5:1). Percent area stenosis ranged from 7% to 54% for vessels with normal reactive hyperemic responses and from 27% to 94% for vessels with abnormal reactive hyperemic responses. With both percent diameter stenosis and percent area stenosis there was substantial overlap between vessels with normal and abnormal reactive hyperemic responses. In contrast, nine of nine vessels with normal reactive hyperemic responses had lesion minimal cross-sectional areas of greater than 3.5 mm2 and 13 of 14 vessels with abnormal reactive hyperemic responses had minimal cross-sectional areas of less than 3.5 mm2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adequate Anticoagulation During Cardiopulmonary Bypass Determined by Activated Clotting Time and the Appearance of Fibrin Monomer

The adequacy of anticoagulation during 2 hours of cardiopulmonary bypass at 30 degrees C in 9 rhesus monkeys was determined by measuring the whole-blood activated clotting time (ACT) and by noting the appearance of thrombin-altered fibrin (fibrin monomer) and the relative consumption of clotting factors. Factor V and VIII, the heparin cofactor, antithrombin III, prothrombin time, partial thromboplastin time, ACT, platelets, hematocrit, fibrinogen, and fibrin monomer were determined prior to heparinization and after protamine. In 6 of 9 experiments, fibrin monomer became positive in the plasma during cardiopulmonary bypass (CPB), indicating that active coagulation was occurring. In 5 of the 6 animals, initial ACT was less than 400 seconds, and fibrin monomer appeared within the first 30 minutes of bypass. In 1 animal with an initial ACT of 439 seconds, fibrin monomer appeared after 60 minutes of bypass, at which time the ACT was less than 400 seconds. An abnormal level of fibrin monomer was not detected in 5 pediatric patients with an ACT greater than 450 seconds during CPB. Our experimental study and clinical data suggest that the lower limit, as measured by the ACT, for anticoagulant effect to provide coagulation-free CPB is at least 400 seconds.

Abnormalities in the coronary circulation that occur as a consequence of cardiac hypertrophy

Myocardial ischemia is frequently observed in patients with cardiac hypertrophy even when the conduit coronary arteries are normal. Recent studies indicate that impaired coronary reserve in hypertrophied hearts probably occurs because growth of the coronary bed does not keep pace with increases in cardiac mass. The imbalance between vascular proliferation and muscle growth is probably most severe when cardiac hypertrophy is produced by pressure overload. Experimental studies also suggest that abnormalities intrinsic to pressure-hypertrophied heart muscle (decreased capillary density; decreased coronary reserve; electrophysiologic abnormalities) adversely affect the response of the enlarged heart to sudden coronary occlusion. When animals with hypertension and left ventricular hypertrophy are subjected to sudden coronary occlusion, the incidence of sudden cardiac death is increased severalfold and infarct size is substantially augmented. These observations suggest that abnormalities in the coronary microcirculation that accompany cardiac hypertrophy play a significant role in the pathogenesis of the complications associated with cardiac hypertrophy.

Prospective study of surgery for left ventricular aneurysm

Abstract To assess the effects of surgery for ventricular aneurysm on left ventricular performance 18 consecutive patients referred for such surgery were Studied prospectively. The patients had the following preoperative findings: ejection fraction by Isotope ventriculogram 28± 4 percent (mean ± standard error), New York Heart Association functional class 3.6 ± 0.1 and left ventricular noncontractile area 28 ± 3 percent by the graphic integration method. Thirteen patients had both angina pectoris and congestive heart failure, two had angina alone and three had congestive heart failure alone. All patients were studied before and after operation with isotope ventriculograms at rest and during exercise and treadmill exercise tolerance tests if their clinical status permitted these studies. Five patients also had postoperative cardiac catheterization. Catheterization data were in close agreement with the results of imaging studies. In 11 patients the aneurysm was resected and in 4 H was plicated; in 3, no discrete aneurysm was found. Sixteen patients including the three with no discrete aneurysm had concomitant coronary bypass grafting. There was no operative death and one late death. After operation, all patients had significant improvement in functional class (postoperative class 2.3 ± 0.1, p

Bypass of Superior Vena Cava with Spiral Vein Graft

The superior vena cava was successfully bypassed in a patient with superior vena cava syndrome due to granulomatous mediastinitis. A spiral vein graft constructed from autogenous vein was utilized. Complete relief of symptoms and graft patency documented by venography six months after the operation confirm the usefulness of this procedure in patients with superior vena cava obstruction.

The Role of Venography and Surgery in the Management of Patients with Superior Vena Cava Obstruction

Venacavography proved to be an excellent guide for the design of patient management programs. Type 1 patients with incomplete obstruction of the superior vena cava (SVC) are best managed by irradiation and chemotherapy regimens and usually do not require operation to bypass the SVC. Types II and IV patients are treated by operation when symptoms of airway obstruction or cerebral venous hypertension are present. Type III patients should be considered for SVC bypass as an initial therapeutic intervention. This group is more likely to have cerebral or airway symptoms and would benefit most from the bypass operation. In terms of operative considerations, type III patients are ideal for operation because the left brachiocephalic vein is usually available for bypass. Type IV patients may also be considered, but operation is more difficult and may require venous thrombectomy or extension of the bypass graft above the thoracic inlet to obtain head and neck decompression.

Operation for Aortic Arch Anomalies

Forty-two patients with aortic arch anomalies resulting in tracheoesophageal compression were treated during the period 1948 through 1978. These anomalies are important causes of upper respiratory and esophageal obstruction in babies and small children and can be corrected safely with excellent relief of symptoms. Nineteen patients (45%) had a right aortic arch with a ligamentum arteriosum, 17 patients (40%) had double aortic arches, and 6 patients (15%) had aberrant right subclavian arteries. Other associated congenital malformation and mental retardation were seen in 15 patients (36%). Diagnosis was accurately made in 38 patients (90%) by barium esophagogram. Basic surgical principles include exposure through a left thoracotomy, complete identification of the aortic arch anatomy, and division of the constricting ring. Surgical treatment resulted in 2 deaths (5%), and 1 patient died late. Early postoperative respiratory complications were common. All survivors were relieved of their symptoms late (median, 94 months) postoperatively.

Surgical Treatment of Atrial Myxomas: Early and Late Results of 11 Operations and Review of the Literature

Eleven patients underwent surgical excision of atrial myxomas during a 15-year period, with no hospital deaths. The operation consisted of excision of the tumor with a generous portion of atrial septum or wall. Patch reconstruction of the atrial septum was required in most patients. There were 2 late deaths (14 and 121 months after operation). Late recurrences have been reported in other series but no recurrences were diagnosed in any of the patients in this series reexamined by echocardiography 7 to 156 months (mean, 48 months) after operation. Late functional results were excellent (78%, New York Heart Association Class D. The pertinent literature is reviewed.