Biomedical subjects
C B Wright
Publications and source records attributed to C B Wright.
Coronary bypass without angiography: an unusual circumstance.
This paper presents an unusual case of an individual with myocardial ischemia, angina pectoris, and myocardial infarction who also had an anaphylactic reaction to angiographic dye. The coronary bypass operation was guided by the use of intraoperative coronary reactive hyperemia assessed by Doppler ultrasound. The patient has had a good response to the operation without additional angina or difficulties.
Coronary obstructive lesions: assessing their physiological significance in humans.
For more than two decades cardiologists and cardiac surgeons have estimated the physiologic significance of coronary lesions by measuring percent stenosis of the obstructive vascular segment from coronary angiograms. Such measurements, when performed without computer-based analysis, are associated with substantial variability between observers, as well as within a single observer. In addition, recent intraoperative measurements of coronary reserve in individual obstructed vessels of patients with multivessel coronary disease performed with a suction Doppler probe indicate that, in the intermediate range (10% to 90% diameter stenosis), percent stenosis measurements of coronary lesions by angiography correlates poorly with coronary reserve. These studies suggest that the physiologic significance of coronary obstructions cannot be accurately assessed by visual interpretation of coronary angiograms. More sophisticated and accurate approaches are needed for assessing the physiologic significance of coronary obstructions preoperatively.
The cost of simultaneous surgical standby for percutaneous transluminal coronary angioplasty.
From November, 1980, to May 1985, 699 patients have undergone percutaneous transluminal coronary angioplasty of 784 lesions at our institutions. Simultaneous surgical standby was available on all cases. One hundred twenty-four patients (18%) underwent immediate myocardial revascularization; 45 (6%) were operated on because the lesion could not be dilated. Seventy-nine patients (11%) underwent immediate operation for an acute complication of angioplasty: coronary occlusion in 45, dissection in 29, coronary perforation in three, and atrial perforation in one. Fourteen patients (18%) required cardiopulmonary resuscitation en route to the operating room, and 10 patients (20%) had insertion of an intra-aortic balloon pump in the cardiac catheterization laboratory. The average time from complication to reperfusion was 87 minutes, ranging from 40 to 165 minutes. An average of 2.0 grafts per patient (ranging from one to five grafts per patient) were performed. Of those 79 patients who underwent operation for an acute complication, one died (1.3%), 31 patients (39%) had a myocardial infarction according to enzyme criteria (creatine kinase-myocardial band greater than 40 IU), and 17 patients (22%) had new Q waves on the electrocardiogram. Good results are related to minimizing the time the myocardium is ischemic. No patient in whom reperfusion was begun in less than 75 minutes had a Q wave infarction or a creatine kinase-myocardial band level greater than 40 IU. Simultaneous surgical standby is the only method allowing immediate access to surgical facilities. A standby team of eight persons and equipment were immediately available for emergency bypass grafting for an average of 3.6 hours (range 1.3 to 5.4 hours per angioplasty attempt). The patient charges for this simultaneous standby were $632.00 per angioplasty attempt, or $442,278.00 for the entire series. The actual cost of the standby was over $1,700.00 per attempt totaling $1,188,843.00 for the 699 patients. This underestimation of the cost of surgical standby has occurred in other series, because little mention has been made of this cost in the published reports on the cost effectiveness of angioplasty. In terms of time demands, over 2,500 hours were spent by surgeons standing by for the 699 attempts. Simultaneous surgical standby is the most effective means of limiting the time the myocardium is ischemic after an angioplasty complication. However, this method is costly, necessitating more of a financial and time commitment than generally anticipated. Future studies of the cost effectiveness of angioplasty should include the cost of surgical standby with accurate per-patient cost accountability.
Renal arteriovenous fistulas: a review of etiology, diagnosis, and management.
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Concomitant cardiac and vascular disease: "through the looking glass".
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Coronary reserve in volume-induced right ventricular hypertrophy from atrial septal defect.
To assess coronary reserve in patients with right ventricular (RV) hypertrophy secondary to volume overload, the quantitative characteristics of coronary reactive hyperemia were examined in 20 patients with a large atrial septal defect (ASD). The control group consisted of 13 patients who had undergone elective cardiac surgery for abnormalities that did not involve the right ventricle or its blood supply. Coronary blood flow velocity was measured in RV branches of the right coronary artery at cardiac surgery. Echocardiographic measurements of RV diameter in ASD and in control patients (2.3 +/- 0.2 and 1.1 +/- 0.2 cm, respectively, p less than 0.05) documented the presence of substantial RV enlargement in patients with ASD. In patients with ASD and in control subjects, a 20-second coronary occlusion produced maximal coronary dilation. After release of a 20 second coronary occlusion, the peak-to-resting velocity ratio in ASD and in control patients was 3.1 +/- 0.2 and 5.5 +/- 0.1, respectively (p less than 0.05). The 50% decrease in the ratio of peak-to-resting coronary blood flow velocity, a measure of relative coronary reserve, in patients with ASD suggests that coronary reserve is compromised in volume-induced RV hypertrophy. These studies support the concept that in humans, volume-induced RV hypertrophy substantially decreases coronary reserve.
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.
Interpretation of Doppler segmental pressures in peripheral vascular occlusive disease.
Measurement of Doppler segmental arterial pressures in the lower extremity using narrow pneumatic cuffs has become a standard noninvasive diagnostic technique. Correlation between arteriographic and noninvasive studies was available for 345 aortoiliac segments and 326 femoropopliteal segments. If stenoses of 50% or greater and occlusions were considered hemodynamically significant, the sensitivity to aortoiliac disease was 97%, but only 67% to femoropopliteal disease. The specificity for hemodynamically insignificant disease was 50% and 68%, respectively. Accuracy was influenced by the presence of associated aortoiliac or femoropopliteal disease. The sensitivity to hemodynamically significant femoropopliteal disease was 55% if there was associated aortoiliac disease, and 89% in its absence. In the presence of significant femoropopliteal disease, specificity for the absence of aortoiliac disease decreased from 70% to 41%.
Successful balloon counterpulsation for right ventricular failure.
We used pulmonary arterial balloon counterpulsation to treat successfully a patient with severe right ventricular failure following mitral valve replacement. The balloon was placed through a vascular graft sutured as a diverticulum to the main pulmonary artery.
Coronary artery bypass surgery following thrombolytic therapy for acute coronary thrombosis.
One hundred thirty-six patients underwent thrombolytic therapy for acute evolving myocardial infarction from June, 1981, through December, 1982. Of these patients, 51 underwent coronary bypass procedures from two hours to 90 days (average, 16 days) following thrombolytic therapy. Six (12%) had single-vessel disease, 15 (29%) had double-vessel disease, and 30 (59%) had triple-vessel involvement. Ejection fraction values ranged from 21 to 60%. The average number of grafts performed per patient was 3.4. There were no operative deaths in this series. Postoperative hemorrhagic problems were minimal, and the incidences were no different from those for other coronary bypass patients. In follow-up ranging from 2 to 18 months, there was no recurrence of severe angina or other clinical evidence of saphenous graft occlusion in the thrombolysed vessels. Of the 45 patients eligible to return to work, 40 (89%) have done so. The data from this series suggest that surgical myocardial revascularization after intracoronary thrombolytic infusion for acute myocardial infarction can be performed safely and that complete recovery and a high return-to-work ratio can be anticipated.
Coronary artery bypass surgery in the elderly.
One hundred fifteen patients over 65 years of age were operated on at our institution for coronary artery bypass grafting (CABG). The operative mortality was 5% compared with an overall operative mortality of 2.5% in the last five years for 1,500 persons with CABG. Increased risk factors included qualification for New York Heart Association (NYHA) class IV, ejection fraction of less than 35%, diffuse disease requiring more than five grafts, and age over 75 years. At one year after operation, 81% of the patients were clinically improved, and the survival rate was 91%. Patients over 65 years of age in NYHA classes II and III with good left ventricular function requiring four or less bypass grafts appeared to have an excellent prognosis both acutely and during a one-year follow-up period.
An unusual case of renal artery hypertension.
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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.
Therapeutic use of albumin: 2.
It has previously been shown that albumin costs in a Veterans Administration Hospital constituted a large portion of the pharmacy drug budget and that much albumin was prescribed inappropriately. Therefore, a program of education and use monitoring was instituted to improve understanding and prescribing of this product. Inappropriate use declined from 41% to 26% of total albumin units and, more dramatically, total cost of albumin used had decreased by 90% one year after this program was initiated. Projected yearly savings from decreased use was more than $85,000. These results demonstrate that such a program can promote more appropriate use of albumin and effect a cost savings for hospitals.
Gastrointestinal bleeding and mycotic superior mesenteric aneurysm.
This is a case report of management of a delayed mycotic superior mesenteric artery aneurysm occurring in a patient 2 years after aortic valve replacement for endocarditis. A chronic ulcer history, anticoagulation therapy, episodic gastrointestinal bleeding associated with negative gastrointestinal series, and gastritis seen at endoscopy delayed the ultimate diagnosis. An episode of massive hemorrhage precipitated angiography with subsequent surgical confirmation of the diagnosis. Management included debridement and extirpation of the major part of the aneurysm, Doppler assessment of the inadequacy of collateral mesenteric arterial blood flow, and restoration of flow with a bypassing saphenous vein graft segment. Although this technique of reconstruction has been suggested, we can find no other report of such a similar case among the few reported surgical successes with superior mesenteric artery mycotic aneurysm.
Aortofemoral bypass grafting: Microvel.
One hundred seventy-five patients underwent elective aortofemoral bypass during the years from 1976 to 1979. One hundred eighteen of these patients received a knitted double velour prosthesis (Microvel) and the remainder received standard knitted Dacron. All patients had been followed for a minimum of 12 months. Early graft thrombosis occurred in three limbs, and these were restored by reoperation for 100 per cent patency at discharge from the hospital. The operative mortality was three patients (1.7%). Complications included myocardial infarction (three/one death), renal failure (one/one death), respiratory failure (one/one death), cerebrovascular accident (four), and superficial wound infection (five). Late complications were infrequent, but included seven graft limb occlusions in six patients (3.4%), and one graft infection, one ureteral obstruction, and one false aneurysm. Among the 256 symptomatic extremities, claudication was completely relieved in 199 (78%) and substantially improved in an additional 48 (18.5%). Hemodynamic assessment with arm/ankle or arm/high thigh indices improved in parallel with symptomatic relief. Thus, only nine (3.5%) symptomatic extremities failed to improve with the proximal reconstruction, requiring distal reconstruction or amputation. The authors remain advocates of aortofemoral grafting with end-to-end proximal anastomosis and hooding of the distal anastomosis over the profunda origin for most aortoiliac occlusive diseases. Our recent experience with double velour graft and this technique have been very satisfactory.
Comparison of continuous-wave Doppler imaging, oculopneumoplethysmography, and the cerebrovascular Doppler examination.
Previous reports of continuous-wave Doppler imaging have combined that technique with periorbital Doppler studies. In the present report, 75 patients with findings suggestive of cerebrovascular insufficiency were evaluated using continuous-wave Doppler imaging, oculopneumoplethysmography (OPG-G) and the cerebrovascular Doppler examination (CDE). Each test was interpreted independently. Doppler imaging had an overall accuracy of 85%, with a 68% accuracy in identifying 50-70% stenoses and a 69% accuracy in identifying high-grade stenoses (greater than 70%) and occlusion. OPG-G had an overall accuracy of 85%, with a 55% sensitivity for 50-70% stenoses and an 89% sensitivity for high-grade stenoses and occlusion. The CDE had an overall accuracy of 84% and a 50% sensitivity for stenoses of 50-70% and an 88% sensitivity for high-grade stenoses and occlusion. As an independent technique, continuous-wave Doppler imaging achieves an overall accuracy comparable to that of OPG-G or the CDE. Its sensitivity to high-grade stenosis and occlusion, however, is less than that of the other techniques. Since CDE and OPG-G had a 94% sensitivity to carotid occlusion and a combined sensitivity to high-grade stenoses and occlusion of 88% and 89%, respectively, their combined use with Doppler imaging offers sensitivity to and differentiation of stenoses from occlusion.