Fabio Giron

Coronary and carotid operations under prospective standardized conditions: incidence and outcome

BACKGROUND No randomized trial has yet evaluated the hypothetical benefit of carotid endarterectomy with coronary artery bypass grafting. This prospective review was undertaken to determine the differences between observed and predicted complication rates, as well as to define new predictors and assess costs in a standardized population. METHODS A prospective nonrandomized study was undertaken over a 4-year period involving all coronary artery bypass graftings done at one institution. Operative procedure was standardized. All patients underwent preoperative screening for carotid disease. If 80% or more stenosis was present, combined coronary artery bypass grafting and carotid endarterectomy was performed. RESULTS Of 2,071 patients, 1,987 had coronary artery bypass grafting only. In that group there were 34 strokes (1.7%) and 41 deaths (2.0%). Eighty-four patients underwent combined coronary artery bypass grafting/carotid endarterectomy and in that group there were four strokes (4.7%) and five deaths (5.9%). Independent risk factors for postoperative stroke were age (odds ratio 1.09; 95% confidence interval 1.04, 1.3), hypertension (odds ratio 2.67; 95% confidence interval 1.22, 5.23), extensively calcified aorta (odds ratio 2.82; 95% confidence interval 1.34, 5.97), and bypass time (odds ratio 1.01; 95% confidence interval 1.00, 1.02). Cost of a stroke was significant (p < 0.05) in both groups. CONCLUSIONS Patients with carotid disease fall into a higher risk group than patients without it. This increased risk is not because of carotid disease alone. Patients without significant carotid disease, who suffered a perioperative stroke, fell into an even higher risk category. Furthermore, carotid endarterectomy was not a significant risk factor by either the univariate or the multivariate analysis.

Wound complications of the retroperitoneal approach to the aorta and iliac vessels

Repeated complaints of postoperative wound pain prompted this review of 113 consecutive vascular operations involving a retroperitoneal approach to the aorta or iliac vessels or both. Flank muscle-splitting incisions (n = 53) had been used to approach the terminal aorta or iliac arteries. Two types of muscle-dividing incisions had also been used: incisions through the eleventh intercostal space (n = 41) to approach the infrarenal aorta; and incisions through the eighth, ninth, or tenth intercostal space with division of the diaphragm (n = 19) to approach the suprarenal aorta. Data on incisional pain, lumbosacral neuritic pain, incisional hernia, and deforming abdominal bulge were culled from the records of follow-up examinations conducted on all patients during periods ranging from 2 to 48 months. Both types of muscle-dividing incisions used to expose the aorta were associated with a 23% (14/60) incidence of abdominal bulge, a 7% (4/60) incidence of incisional hernia, and, more important, a 37% (22/60) incidence of prolonged disabling pain. Thus, although retroperitoneal exposure may be the preferred or the safest approach to certain aortic lesions, its routine use via muscle-dividing incisions is not recommended when the proposed operation can be carried out equally well by the conventional midline transperitoneal approach.

Modeling Stroke Risk After Coronary Artery Bypass and Combined Coronary Artery Bypass and Carotid Endarterectomy

Background and Purpose— The goals of this study were to compare the ability of statewide and institutional models of stroke risk after coronary artery bypass (CAB) to predict institution-specific results and to examine the potential additive stroke risk of combined CAB and carotid endarterectomy (CEA) with these predictive models. Methods— An institution-specific model of stroke risk after CAB was developed from 1975 consecutive patients who underwent nonemergent CAB from 1994 to 1999 in whom severe carotid stenosis was excluded by preoperative duplex screening. Variables recorded in the New York State Cardiac Surgery Program database were analyzed. This model (model I) was compared with a published model (model II) derived from analysis of the same variables using New York statewide data from 1995. Predicted and observed stroke risks were compared. These formulas were applied to 154 consecutive combined CAB/CEA patients operated on between 1994 and 1999 to determine the predicted stroke risk from CAB alone and thereby deduce the maximal added risk imputed to CEA. Results— Risk factors common to both models included age, peripheral vascular disease, cardiopulmonary bypass time, and calcified aorta. Additional risk factors in model I also included left ventricular hypertrophy and hypertension. Risk factors exclusive to model II included diabetes, renal failure, smoking, and prior cerebrovascular disease. Our observed stroke rate for isolated CAB was 1.7% compared with a rate predicted with model II (statewide data) of 1.56%. The observed stroke rate for combined CEA/CAB was 3.9%. When the Stony Brook model (model I) based on patients without carotid stenosis was used, the predicted stroke rate was 2.8%. When the statewide model (model II), which included some patients with extracranial vascular disease, was used, the predicted stroke rate was 3.4%. The differences between observed and predicted stroke rates were not statistically significant. Conclusions— Estimation of stroke risk after CAB was similar whether statewide data or institution-specific data were used. The statewide model was applicable to institution-specific data collected over several years. Common risk factors included age, aortic calcification, and peripheral vascular disease. The observed differences in the predicted stroke rates between models I and II may be due to the fact that carotid stenosis was specifically excluded by duplex ultrasound from the patient population used to develop model I. Modeling stroke risk after CAB is possible. When these models were applied to patients undergoing combined CAB/CEA, no additional stroke risk could be ascribed to the addition of CEA. Such models may be used to identify groups at increased risk for stroke after both CAB and combined CAB/CEA. The ultimate place for CEA in patients undergoing CAB will be defined by prospective randomized trials.

Combined coronary artery bypass and carotid endarterectomy: long-term results.

PURPOSE We determined late survival, freedom from late stroke, and freedom from late cardiac events in patients treated by combined coronary artery bypass and carotid endarterectomy (CAB/CEA). METHODS All patients who underwent CAB/CEA in our institution between January 1994 and December 1999 were identified. Follow-up data were obtained from office records and telephone interviews. Endpoints included death from any cause, stroke, and non-fatal cardiac events (MI, CHF, percutaneous transluminal angioplasty with stenting, redo CAB). Data were expressed in life table format. RESULTS Over a 6-yr period 154 patients had combined CAB/CEA with a 3.9% postoperative stroke rate. Six patients (3.9%) died, leaving 148 patients for follow-up. Average follow-up was 38 +/- 23 months (range: 1-82 months). During the follow-up period two patients (1.4%) had late strokes and 17 patients (11%) had late non-fatal cardiac events. The late mortality rate was 13% (19 patients). Of the late mortalities, four were related to cardiac disease and one to stroke. Using Kaplan-Meier analysis, the 5-yr survival probability was 80 +/- 4.3%. The freedom from late ipsilateral neurologic events was 98 +/- 1.3% at 5 yr. The freedom from late cardiac events was 82 +/- 4.6% at 5 yr. CONCLUSIONS The large majority of patients with combined coronary and carotid artery disease can be expected to live for greater than 5 yr. Therefore, these patients should be considered candidates for prophylactic CEA for stroke prevention, even when their carotid lesions are asymptomatic. Successful CAB/CEA provides good long-term survival and freedom from late cardiac events, as well as excellent freedom from late stroke. Further reduction in perioperative events will make this operative approach even more attractive in patients with combined disease.

Clinical and chemical characterization of an adventitial popliteal cyst

We present further evidence that adventitial cysts of the popliteal artery are ganglions, based on studies of a lesion found in a 51-year-old man. The cyst was located entirely within the adventitia, lacked a cellular lining, and did not communicate with either the arterial lumen or the synovial space. The contents were gel-like and composed of 1.64 gm of hyaluronic acid and 0.20 gm of protein per dl. This material did not possess boundary-lubricating ability in a test system that slides natural latex rubber against glass. The histologic appearance, chemical composition, and absence of lubricating ability more closely resemble the characteristics of ganglions. These findings suggest that the cyst was not synovial but rather ganglionic in origin.

After the blue toe: Prognosis of noncardiac arterial embolization in the lower extremities

PURPOSE To better understand the prognosis of atheroembolic disease, we reviewed the outcomes of 41 patients with embolization to the viscera and lower extremities. METHODS AND RESULTS All cases involved emboli that originated from a radiographically identified proximal arterial source. There were 30 men and 11 women (mean age 65 years; mean follow-up time 2 years), and all had been first treated for this condition within the past 6 years. The overall mortality rate was 17% (7/41) and the rate of recurrent embolization 15% (6/41). To compare outcomes associated with supradiaphragmatic versus subdiaphragmatic disease, we defined two groups: group 1 comprised patients (n = 5) in whom the identified embolic source extended above the diaphragm, and group 2 comprised patients (n = 36) in whom the source remained below the diaphragm. The mortality rates in groups 1 and 2 were 60% (3/5) and 11% (4/36), respectively (p < 0.05). Recurrent embolization was also significantly higher in group 1 (60% vs 8%, p < 0.025). There were two amputations in group 1 and six in group 2 (p = not significant). Group 2 patients were then divided into two subgroups: those with limited disease (n = 19) in which the emboli had a single, radiographically identified source (i.e., aneurysm or single area of ulcerated plaque) and those with diffuse disease (n = 17) in which the emboli had multiple, radiographically identified potential sources. In the subgroup of patients with limited disease, no deaths or episodes of recurrent embolization occurred, whereas four deaths and three episodes of recurrent embolization occurred in the subgroup of patients with diffuse disease. The differences in these outcomes, however, were not statistically significant. Thirty selected patients (one from group 1 and 29 from group 2) underwent operation on or bypass of the imputed lesion. Only one (7%) of these 30 patients had recurrent embolization. In contrast, recurrent embolization was noted in four (36%) of the 11 patients who did not have an operation directed at the lesion (p < 0.025). No significant difference in mortality was found between patients who underwent operation and those who did not. CONCLUSIONS Patients with atheroemboli have a substantial mortality rate and risk of recurrent embolization, especially if the disease process extends above the diaphragm; but in selected patients, operation may decrease the frequency of recurrence without increasing mortality.

The effects of endothelial injury on smooth muscle cell proliferation

The endothelial injury induced by the placement of a synthetic graft has been implicated as a stimulus for the development of MIH. In this study we compared the degree of EC coverage and the early SMC-PR in the arterial segments proximal and distal to 2 mm diameter PTFE grafts that had been placed in rabbit carotid arteries (n = 49). In vivo labeling with 3H-thymidine and Evans blue was carried out at intervals of 2 to 33 days after grafting. The SMC-PR was measured as the degree of 3H-labeled DNA divided by the total DNA for each segment, and the EC coverage was determined by planimetry of the area of Evans blue exclusion. There was an early rise in the SMC-PR in both arterial segments, but it was more marked in the distal segment (p less than 0.001). There was no correlation between the SMC-PR and the degree of EC coverage in either the proximal (r = 0.25) or the distal segments (r = 0.10). The data suggest that there is a greater SMC-PR at the distal end of an implanted PTFE graft. The degree of endothelial loss and its regrowth does not appear to be an important factor.

The early and late responses of the arterial wall to graft placement.

The relationship between the early smooth muscle cell proliferative response (SMC-PR) to injury and the later development of myointimal hyperplasia (MIH) complicating arterial bypass grafts remains unclear. In the present study, the early SMC-PR and the later MIH induced by a 2-mm-diameter PTFE graft placed in a rabbit carotid were compared with the response induced by an autogenous artery (AA) graft in the contralateral carotid. The early SMC-PR was measured in the proximal and distal arterial segments 5 days after graft placement by in vivo labeling with [3H]thymidine to determine the DNA specific activity (DNA-SA). The later anastomotic MIH was measured 16 and 32 weeks postgrafting by calculating the intimal/medial ratio. There was a marked and similar increase in the early SMC-PR noted with both the AA and the polytetrafluoroethylene (PTFE) grafts. The distal segments demonstrated a significantly higher DNA-SA when compared to the proximal in both AA- and PTFE-grafted arteries. There was a moderate degree of anastomotic MIH noted in chronic grafts; however, a regression in intimal thickening was observed over time in the AA-grafted arteries, while the distal anastomosis of the PTFE-grafted vessels demonstrated a continuous progression of the MIH process. The early SMC-PR may abate in arteries grafted with autogenous grafts, but there is a persistent proliferative response at the distal anastomosis associated with synthetic grafts.