James A. DeWeese

Unstable angina pectoris: National cooperative study group to compare surgical and medical therapy: II. In-Hospital experience and initial follow-up results in patients with one, two and three vessel disease

Abstract A prospective randomized study comparing intensive medical therapy with urgent coronary bypass surgery for the acute management of patients with unstable angina pectoris was carried out by nine cooperating medical centers under the auspices of the National Heart, Lung, and Blood Institute. Between 1972 and 1976, a total of 288 patients were entered into the study. All patients had transient S-T or T wave changes, or both, in the electrocardiogram during pain; 90 percent had pain at rest in the hospital, and 76 percent had multivessel coronary disease. The medically and surgically treated patients were comparable with respect to clinical, electrocardiographic and angiographic characteristics and left ventricular function. During the total study period, the hospital mortality rate was 5 percent in the surgical group and 3 percent in the medical group (difference not significant). The rate of in-hospital myocardial infarction was 17 and 8 percent in the respective groups (P In the 1st year after hospital discharge class III or IV angina (New York Heart Association criteria) was more common in medically than in surgically treated patients with one vessel disease (22 percent versus 3 percent, P The results indicate that patients with unstable angina pectoris can be managed acutely with intensive medical therapy, including the administration of propranolol and long-acting nitrates in pharmacologic doses, with adequate control of pain in most patients and no increase in early mortality or myocardial infarction rates. Later, elective surgery can be performed with a low risk and good clinical results if the patients angina fails to respond to intensive medical therapy.

Transfemoral endovascular aortic graft placement

PURPOSE The purpose of this study was to develop an endovascular system for transfemoral placement of straight aortic grafts and bifurcated aortoiliac grafts. METHODS Both types of graft consist of barbed, self-expanding stents attached to a woven polyester fabric. Survival studies of straight-graft function were performed in six large mongrel dogs. Digital subtraction fluoroscopic equipment was used to guide insertion and record angiograms at 0, 1, and 3 months. Bifurcated grafts were inserted in an additional eight dogs, four with distal stents and four without. Straight grafts were inserted into six cadaveric aortas (five atherosclerotic and one aneurysmal; age 68.7 + 5.7 years) to assess stent attachment. RESULTS Angiograms obtained immediately after straight-graft insertion showed placement to be within 4.6 + 1.6 mm of the intended level. Follow-up angiograms at 1 and 3 months showed no migration, no leakage, and patency of all six grafts. After bifurcated graft insertion there were no angiographic signs of perigraft leakage, with or without distal stents. The mean force required to displace straight grafts 10 mm from their original position in cadaveric aortas was 1388 + 127 g. CONCLUSION These preliminary results show that straight and bifurcated endovascular grafts can be positioned accurately and securely in the abdominal aorta.

An evaluation of new methods of expressing aortic aneurysm size: Relationship to rupture

The diameter of aortic aneurysms were standardized to measures of patient size and normal aortic size in an effort to define indexes that might be more predictive of aneurysm rupture than raw aneurysm diameter alone. Normal aortic diameters were measured in 100 patients undergoing abdominal CT scans for other reasons, and an average infrarenal aortic diameter of 2.10 +/- 0.05 cm was observed. Normal aortic diameter was dependent on both age and sex, ranging from 1.71 +/- 0.06 cm in women below age 40 years to 2.85 +/- 0.04 cm in men above age 70 years. Overall, 11 (5.1%) of the ruptures occurred in aneurysms less than 5 cm in diameter, and four (1.9%) occurred in aneurysms less than 4.0 cm in diameter. When the CT scans of 100 patients undergoing elective aneurysm resection were compared with those of 36 patients with ruptured aneurysms, no threshold diameter value accurately discriminated between the two groups. However, standardization of the aneurysm diameter to the transverse diameter of the third lumbar vertebral body as an index of patient body size produced an accurate predictor of rupture when a threshold ratio of 1.0 was used. No aneurysm ruptured below this ratio, but 29% of elective aneurysms were smaller than the vertebral body diameter. Receiver operating characteristic curve analysis confirmed the superiority of the aneurysm to vertebral body diameter ratio as a discriminator of ruptured aneurysms. It appears that aneurysm diameter alone is not sufficiently predictive of rupture to be used as the sole indication for elective resection.

Factors determining survival after ruptured aortic aneurysm: The hospital, the surgeon, and the patient ☆

The 10-year experience of a single community was reviewed and a multivariate analysis was performed to determine the relative importance of clinical and environmental factors in mortality after ruptured abdominal aortic aneurysm resection. Ruptured aneurysms were repaired in 243 patients in six area hospitals (one university, five community) by 25 surgeons (16 vascular, 9 general). Overall, 30-day mortality was 55% (133/243). Although the mortality by hospital ranged from 44% to 68%, these differences were not statistically significant. However, significant variations occurred in the mortality rates of individual surgeons, ranging from 44% to 73%. The mortality rate for the vascular surgeons was less than that of the general surgeons, 51% versus 69% (p less than 0.05). Clinical factors were evaluated, and the most significant parameters were systolic blood pressure, presence of chronic obstructive lung disease, and history of chronic renal insufficiency. These results support the implication that the degree of specialization of the surgeon and the preexisting health of the patient are the most important determinants of survival after ruptured abdominal aortic aneurysm. The size and sophistication of the hospital appear to be less influential factors.

Multicenter validation study of real-time (B-mode) ultrasound, arteriography, and pathologic examination.

The ability of high-resolution ultrasound, angiography, and pathologic examination of endarterectomy specimens to identify and quantitate atherosclerosis was compared in a five-center study. The carotid bifurcation in 900 patients was evaluated by angiography and ultrasound. In 216 cases, high-quality endarterectomy specimens were available for comparison with the preoperative images. All comparisons were made in a blinded fashion. Results indicate that ultrasound is able to differentiate angiographically normal from abnormal arteries with a sensitivity of 88% (1077 of 1233 arteries) and accuracy of 79% (1251 of 1578 arteries). Angiographic stenoses equal to or greater than 50% diameter were accurately identified by ultrasound imaging in 72% (1133 of 1578 arteries) of cases, and this was improved by the addition of other functional data (i.e., Doppler spectral analysis and oculoplethysmography). There was only modest correlation of absolute measurements of lesion width, minimal lumen, and standard lumen by the two imaging techniques (r = 0.28 to 0.55). Ultrasound measurements of lesion width were on the average 2 mm greater than those of angiography. The lumen averaged 1.5 mm larger when measured by ultrasound techniques. In the subset in which data were available from endarterectomy specimens, ultrasound showed the best correlation with lesion width (mean difference -1.1 mm) and angiography correlated best with minimal lumen (mean difference -0.1 mm). Neither examination consistently identified ulcerated plaques. Although ultrasound imaging alone has limited usefulness in quantitating luminal stenosis, this can be improved by the use of Doppler spectral analysis and oculoplethysmography. Ultrasound is superior to angiography for quantifying atherosclerotic plaque (lesion width) and will be an important tool for further study of atherosclerotic lesions.

Survival improvement following aortic aneurysm resection.

Abdominal aortic aneurysm resections were performed on 298 patients between January, 1966 and December, 1973. The results were compared with 186 resections previously reported between 1955-1965. Hospital mortality rates for elective resections were 13% in 1955-1965, 8.4% in 1966-1973, and 4.2% in the 113 patients treated during the last 3 years. Urgent resections for intact aneurysms, previously associated with a 36% mortality, resulted in a 6% mortality rate in 1966-1973. The emergency resection mortality rate for ruptured aneurysm, originally 69%, was reduced to a present day over-all mortality of 55%, and 42% for the last 3 years. Calculated actuarial survival at 5 years was 65% for urgent (intact), 60% for elective and 40% for emergency (ruptured) groups. Atherosclerosis remains the major deterrent to long-term survival with myocardial infarction and stroke causing 43% of deaths occurring within 5 years. Improved survival appeared secondary to better operative technique, postoperative patient monitoring, increased surgical experience, and more elective resections of smaller, asymptomatic aneurysms than in 1955-1965. With present day low mortality rates, elective resection should be recommended in all patients without significant medical contraindications.

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm.

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)

Fate of the proximal aortic cuff: Implications for endovascular aneurysm repair☆☆☆

PURPOSE Long-term success of endoluminally placed grafts for exclusion of abdominal aortic aneurysms (AAAs) relies on secure fixation at the proximal and distal cuffs and, as such, assumes that the fixation sites will not dilate over time. Data regarding this issue, however, are not yet available. This study was performed to evaluate the region of the proximal anastomosis in patients many years after having undergone conventional AAA repair to determine the potential for late dilatation after placement of an endoluminal device. METHODS Three hundred forty-six patients underwent repair of an infrarenal AAA at our institution between January 1985 and December 1990. Of 97 eligible living patients, 33 both had their original CT scans available and underwent repeat scanning at a mean of 88.6 +/- 23.8 months (mean +/- SD; range, 40 to 134 months) after repair. RESULTS The overall 5-year survival rate was 73%. The mean preoperative infrarenal aortic cuff diameter by CT scan was 24.5 +/- 3.7 mm (range, 19 to 33 mm). At an average of 89 months after repair, the mean infrarenal aortic diameter increased 4.3 mm to 28.8 +/- 7.7 mm (range, 20 to 52 mm; p = 0.0004 by t test). The proximal cuff at this time measured 30 mm or more in 11 patients (33%), and as early as 6 years after operation three of the seven patients (43%) scanned within this time period had cuffs that were dilated to 30 mm or more. Late dilatation to 30 mm or more was rare (16%) in patients who had preoperative cuffs that measured 27 mm or less. The mean late iliac artery size was 16.9 +/- 8.9 mm (range, 10 to 52 mm), and 30% (10 of 33) measured 20 mm or more. CONCLUSIONS One third of all patients who survive AAA repair experience significant dilatation of their proximal aortic cuff over time. Proximal dilatation is rare but not absent in patients who have smaller initial aortic cuff diameters. This dilatation rarely causes problems after conventional suture fixation, but the long-term implications of cuff dilatation after endoluminal repair are unclear. Our findings suggest that endovascular aortic prostheses that have the ability to continue to self-expand many years after implantation may be required and that endovascular prostheses may not be the best option for patients who have a long life expectancy or for those who have preoperative proximal cuffs greater than 27 mm.

Unstable angina pectoris: National cooperative study group to compare medical and surgical therapy

A preliminary report is presented of a prospective randomized trial conducted by eight cooperative institutions under the auspices of the National Heart and Lung Institute to compare the effectiveness of medical and surgical therapy in the management of the acute stages of unstable angina pectoris. To date 150 patients have been included in the randomized trial, 80 assigned to medical and 70 to surgical therapy; the clinical presentation, coronary arterial anatomy and left ventricular function in the two groups are similar. Some physicians have been reluctant to prescribe medical or surgical therapy by a random process, and the eithical basis of the trial has been questioned. Since there are no hard data regarding the natural history and outcome of therapy for unstable angina pectoris, randomization appears to provide a rational way of selecting therapy. Furthermore, subsets of patients at high risk may emerge during the process of randomization. The design of this randomized trial is compared with that of another reported trial. Thus far, the study has shown that it is possible to conduct a randomized trial in patients with unstable angina pectoris, and that the medical and surgical groups have been similar in relation to the variables examined. The group as a whole presented with severe angina pectoris, either as a crescendo pattern or as new onset of angina at rest, and 84 percent had recurrence of pain while in the coronary care unit and receiving vigorous medical therapy. It is anticipated that sufficient patients will have been entered into the trial within the next 12 months to determine whether medical or surgical therapy is superior in the acute stages of unstable angina pectoris.Abstract A preliminary report is presented of a prospective randomized trial conducted by eight cooperative institutions under the auspices of the National Heart and Lung Institute to compare the effectiveness of medical and surgical therapy in the management of the acute stages of unstable angina pectoris. To date 150 patients have been included in the randomized trial, 80 assigned to medical and 70 to surgical therapy; the clinical presentation, coronary arterial anatomy and left ventricular function in the two groups are similar. Some physicians have been reluctant to prescribe medical or surgical therapy by a random process, and the ethical basis of the trial has been questioned. Since there are no hard data regarding the natural history and outcome of therapy for unstable angina pectoris, randomization appears to provide a rational way of selecting therapy. Furthermore, subsets of patients at high risk may emerge during the process of randomization. The design of this randomized trial is compared with that of another reported trial. Thus far, the study has shown that it is possible to conduct a randomized trial in patients with unstable angina pectoris, and that the medical and surgical groups have been similar in relation to the variables examined. The group as a whole presented with severe angina pectoris, either as a crescendo pattern or as new onset of angina at rest, and 84 percent had recurrence of pain while in the coronary care unit and receiving vigorous medical therapy. It is anticipated that sufficient patients will have been entered into the trial within the next 12 months to determine whether medical or surgical therapy is superior in the acute stages of unstable angina pectoris.

Anatomic and Hemodynamic Correlations in Carotid Artery Stenosis

Pressures were measured in the carotid arteries of 61 patients proximal and distal to atherosclerotic plaques which were carefully studied by angiography and anatomical dissection. (1) An atherosclerotic plaque causing a constriction of less than 47% luminal diameter leaving a lumen greater than 3.0 mm in diameter never caused pressure drops of greater than 10 mm Hg. Stenoses of greater than 63% luminal diameter leaving lumens less than 1.0 mm in diameter always caused pressure drops. (2) Atherosclerotic plaques producing defects which narrowed the lumen fell into a distinct pattern: (a) Type 1 lesions—This basic lesion filled the bulb of the internal carotid artery near its origin, causing a 1 to 2 cm smooth elliptical encroachment on the lumen. (b) Type 2 lesions—Short localized areas of thickening in addition to the basic lesion caused bar-like defects of the lumen at the origin of the internal carotid artery or near the distal end of the lesion. (c) Type 3 lesions—Multiple bar-like defects were sometimes seen. (d) Type 4 lesions—The areas of increased thickening of the lesion were sometimes quite narrow, producing diaphragm-like defeats on the lumen. Although theoretically these various types of stenoses should produce different hemodynamic changes, insufficient numbers of observations were made to corroborate these presumptions. (3) Angiograms in general mimicked the gross appearance of the plaques and predicted the actual degree of stenosis produced but did not identify many diaphragm defects, ulcerations, or small thrombi.