William C. Mackey

Management of atherosclerotic carotid artery disease: Clinical practice guidelines of the Society for Vascular Surgery

The Society for Vascular Surgery (SVS) appointed a committee of experts to formulate evidence-based clinical guidelines for the management of carotid stenosis. In formulating clinical practice recommendations, the committee used systematic reviews to summarize the best available evidence and the GRADE scheme to grade the strength of recommendations (GRADE 1 for strong recommendations; GRADE 2 for weak recommendations) and rate the quality of evidence (high, moderate, low, and very low quality). In symptomatic and asymptomatic patients with low-grade carotid stenosis (<50% in symptomatic and <60% in asymptomatic patients), we recommend optimal medical therapy rather than revascularization (GRADE 1 recommendation, high quality evidence). In symptomatic patients with moderate to severe carotid stenosis (more than 50%), we recommend carotid endarterectomy plus optimal medical therapy (GRADE 1 recommendation, high quality evidence). In symptomatic patients with moderate to severe carotid stenosis (>/=50%) and high perioperative risk, we suggest carotid artery stenting as a potential alternative to carotid endarterectomy (GRADE 2 recommendation, low quality evidence). In asymptomatic patients with moderate to severe carotid stenosis (>/=60%), we recommend carotid endarterectomy plus medical management as long as the perioperative risk is low (GRADE 1 recommendation, high quality evidence). We recommend against carotid artery stenting for asymptomatic patients with moderate to severe (>/=60%) carotid artery stenosis (GRADE 1 recommendation, low quality evidence). A possible exception includes patients with >/=80% carotid artery stenosis and high anatomic risk for carotid endarterectomy.

Carotid endarterectomy contralateral to an occluded carotid artery: Perioperative risk and late results

To define better the short-term risk and long-term benefit of carotid endarterectomy opposite an occluded carotid artery, we reviewed our experience since 1961. Angiographic data are available for 598 of 670 (89.3%) patients in our carotid registry. In 63 (10.5%) patients the internal or common carotid artery on the side opposite the endarterectomy was occluded. All operations were carried out under general anesthesia with selective shunting based on electroencephalographic criteria. Shunting was required in 29 of 63 (46.0%) patients with contralateral occlusion and 72 of 535 (13.5%) control subjects (p less than 0.0001). Perioperative strokes occurred in 3 of 63 (4.8%) patients with contralateral occlusion and 14 of 535 control subjects (2.6%) (p = 0.23). Perioperative death occurred in 0 of 63 patients with contralateral occlusion and 6 of 535 (1.1%) control subjects (p = 0.40). Life-table cumulative stroke-free rates at 1, 5, and 10 years were 95.2%, 91.0%, and 76.2% in the group with contralateral occlusion and 96.0%, 89.4%, and 84.1% in control subjects (p = 0.25). Life-table cumulative survival rates at 1, 5, and 10 years were 93.1%, 80.8%, and 75.4% in the group with contralateral occlusion and 94.8%, 77.0%, and 57.9% in control subjects (p = 0.58). Carotid endarterectomy contralateral to an occluded carotid artery may be carried out with acceptable risk and late stroke-free and survival rates comparable to those seen in other patients who have undergone carotid endarterectomy.

Treatment of calcific aortic stenosis by balloon valvuloplasty

Recent reports have established the feasibility of using balloon valvuloplasty to reduce left ventricular outflow tract obstruction due to a calcified aortic valve. The present study summarizes experiences with this technique in 9 patients (7 women, 2 men, mean age 78 years) in whom balloon valvuloplasty was used to treat calcific aortic stenosis. Peak aortic valve gradient (mm Hg) decreased from 68 +/- 8 (mean +/- standard error of the mean) before valvuloplasty to 35 +/- 5 after valvuloplasty (p = 0.003). Mean aortic valve gradient decreased from 57 +/- 7 before valvuloplasty to 30 +/- 5 after valvuloplasty (p = 0.006). Calculated aortic valve area increased from 0.42 +/- 0.04 to 0.81 +/- 0.06 cm2 (p = 0.005). Balloon valvuloplasty failed to diminish aortic valve obstruction in only 1 patient who, at subsequent surgery, had a congenitally bicuspid aortic valve. Significant aortic regurgitation was not observed in any of the 9 patients after valvuloplasty. One patient did have a highly focal, presumably embolic, brain stem infarct during the procedure. Femoral arterial blood loss, related to wire-guided exchange of balloon catheters too large for a 12Fr introducer sheath, was minimized by direct arterial exposure in 8 of the 9 patients. Thus, these findings confirm the efficacy of balloon valvuloplasty for the treatment of calcific aortic stenosis. The procedure, however, is not without hazard.

Duplex assessment of venous reflux and chronic venous insufficiency: The significance of deep venous reflux

PURPOSE This study was undertaken to examine the role of superficial and deep venous reflux, as defined by duplex-derived valve closure times (VCTs), in the pathogenesis of chronic venous insufficiency. METHODS Between January 1992 and November 1995, 320 patients and 500 legs were evaluated with clinical examinations and duplex scans for potential venous reflux. VCTs were obtained with the cuff deflation technique with the patient in the upright position. Imaging was performed at the saphenofemoral junction, the middle segment of the greater saphenous vein, the lesser saphenous vein, the superficial femoral vein, the profunda femoris vein, and the popliteal vein. Not all patients had all segments examined because tests early in the series did not examine the profunda femoris or lesser saphenous vein and because some patients had previous ligation and stripping or venous thrombosis. VCTs were examined for individual segment reflux, grouped into superficial and deep systems, and then correlated with the clinical stage as defined by the SVS/ISCVS original reporting standards in venous disease. Segment reflux was considered present if the VCT was greater than 0.5 seconds, and system reflux was considered present if the sum of the segments was greater than 1.5 seconds. Between-group differences were analyzed with analysis of variance and post hoc tests where appropriate. RESULTS Sixty-nine limbs studied were in class 0, 149 limbs were in class 1, 168 limbs were in class 2, and 114 limbs were in class 3. VCTs in the superficial veins were significantly lower in class 0 than in the other clinical classes. There was no difference in superficial reflux in the symptomatic limbs (classes 1 to 3). Reflux VCTs in the superficial femoral and popliteal veins increased as the clinical symptoms progressed, with a significant increase in class 3 ulcerated limbs when compared with nonuclerated limbs. The incidence of deep venous reflux was 60% in class 3 limbs, compared with 29% in class 2 limbs, whereas the incidence of superficial venous reflux did not differ among the symptomatic limbs. Isolated superficial femoral and popliteal vein reflux was uncommon, even in class 3 limbs, but combined superficial femoral and popliteal vein reflux was found in 53% of class 3 limbs, compared with 18.5% of class 2 limbs. CONCLUSIONS Reflux in the deep venous system plays a significant role in the progression of chronic venous insufficiency. Deep system reflux increases as clinical changes become more severe, with significant axial reflux contributing to ulcer formation.

Correlation of clinical findings with venous hemodynamics in 386 patients with chronic venous insufficiency

Deep venous insufficiency secondary to deep valvular incompetence predominated over superficial venous insufficiency in an unselected patient population with advanced chronic venous insufficiency. Venous obstruction was uncommon (5 percent), suggesting that venous bypass surgery may have limited applicability in the management of chronic venous insufficiency. Although the majority of patients (72 percent) with stage III venous disease (ulcer) had deep venous insufficiency alone and would be potential candidates for deep valvular reconstruction, 13 percent were found to have superficial venous insufficiency alone, and the remaining 15 percent, deep venous insufficiency with a hemodynamically significant component of superficial venous insufficiency. These findings suggest that not all patients with stage III disease have altered hemodynamics on the basis of deep venous valvular incompetency. Although most stage III chronic venous insufficiency is secondary to altered deep venous hemodynamics, as demonstrated by shortened venous refill time, there is a significant group of patients with severe chronic venous insufficiency having superficial venous insufficiency alone or in combination with deep venous insufficiency (28 percent). Thus, it is imperative that those patients with superficial venous insufficiency be identified by a widely available and reproducible method, such as light reflection rheography, since they may respond to surgery of the superficial venous system alone.

Brain edema after carotid surgery.

Article abstract-The postoperative hyperperfusion syndrome describes an abrupt increase in blood flow with loss of autoregulation in surgically reperfused brain. Reports described a spectrum of findings, including severe headache, transient ischemia, seizures, and intracerebral hemorrhage. Hypertension is common after carotid artery surgery and often plays a role in the pathophysiology. We now report five patients with severe white matter edema after carotid surgery, a finding not previously included in the hyperperfusion syndrome. Five to 8 days after carotid surgery and after hospital discharge, each patient developed hypertension, headache, hemiparesis, seizures, and aphasia or neglect due to severe white matter edema ipsilateral to the carotid surgery. One patient had a small hemorrhage within the edematous area. Hypertension was severe in four patients and moderate in one. The carotid artery was patent by ultrasound or angiography in each patient after surgery. Transcranial Doppler showed increased velocities ipsilateral to surgery in two patients and bilaterally in one. Computed tomographic abnormalities and neurologic signs resolved within 3 weeks in four of the five patients treated with antihypertensives and anticonvulsants. The fifth patient died from herniation secondary to massive edema. Brain edema with focal neurologic signs should be included as a serious but potentially reversible component of the postoperative hyperperfusion syndrome. NEUROLOGY 1996;46: 175-181

Long-term results with the above-knee popliteal expanded polytetrafluoroethylene graft.

Since approximately 30% to 40% of autogenous vein bypass grafts to the femoropopliteal level may occlude within 5 years of implantation, additional vein will be required for subsequent revisions. We undertook a study to determine whether the preferential use of an above-knee expanded polytetrafluoroethylene bypass graft to save vein is an appropriate option. We reviewed our experience with 114 above-knee expanded polytetrafluoroethylene bypass reconstructions. Life-table analysis of primary and secondary graft patency was carried out by the method of Peto and statistically analyzed for the influence of clinical indication, runoff as determined by both preoperative and intraoperative completion arteriography, smoking, and diabetes. The 5-year primary patency rate of 57% for patients with claudication was comparable to contemporary randomized or retrospective series with below-knee autogenous vein for that indication, and it was superior to the patency rate for limb salvage. The status of the runoff vessels was an important determinant of outcome. The 59 limbs with good arteriographic runoff (2 to 3 vessels) had a markedly higher 5-year patency rate (70%) than the poor arteriographic runoff (0 to 1 vessels) group (30%). Continued cigarette smoking and diabetes mellitus also appeared to affect adversely primary graft patency in our hands. Our data support the use of preferential above-knee expanded polytetrafluoroethylene grafts in patients with good angiographic runoff. This approach does not appear to prejudice the limb against secondary revisionary procedures or the use of a new autogenous graft, if required.

An assessment of the positive predictive value and cost-effectiveness of dipyridamole myocardial scintigraphy in patients undergoing vascular surgery

PURPOSE The approach to cardiac risk stratification of patients undergoing vascular surgery continues to be controversial. The success of algorithms that use clinical risk factors to determine cardiac risk have been inconsistent. Dipyridamole myocardial scintigraphy (DMS) has been accepted as a sensitive, noninvasive approach to risk stratification with excellent negative predictive value. Low positive predictive value (PPV) of abnormal DMS scans is a shortcoming that contributes to extensive preoperative cardiac evaluation and intervention with associated morbidity, mortality, and cost in most patients who undergo uncomplicated vascular procedures, regardless of DMS results. METHODS Over 6 years, 237 patients underwent DMS before surgical management of infrarenal aortic aneurysm, aortoiliac, or infrainguinal occlusive disease. The value of multiple clinical factors and DMS were assessed retrospectively for the prediction of perioperative myocardial infarction (MI), heart-related death, or preoperative selection for myocardial revascularization. Only congestive heart failure and two or more reversible defects on DMS were statistically significant on logistic regression analysis. RESULTS The PPV of DMS was 19% for all patients with reversible defects, 12% for patients with one reversible defect, and 36.7% for patients with two or more reversible defects. The rates of cardiac death and MI were 1.3% and 5.9%, respectively. Perioperative echocardiography revealed unchanged postinfarction ejection fraction in most patients who experienced MI. Cost-effectiveness of DMS screening was evaluated. CONCLUSIONS The costs per MI and cardiac death averted suggest a decline in cost-effectiveness of screening with DMS over time, assuming improving cardioprotective strategies of patient care. Clinical risk factors were minimally useful in the prediction of perioperative MI, heart-related death, or need for myocardial revascularization. The PPV of DMS is low, and the majority of MIs may be clinically insignificant. The cost-effectiveness of cardiac screening with DMS may not be justifiable given current trends of health care reform.

Management of recurrent carotid stenosis: Should asymptomatic lesions be treated surgically?

PURPOSE The purpose of this study was to determine factors that may influence patient selection for surgery in recurrent carotid stenosis (RCS) and to contrast the results of primary and secondary carotid endarterectomy (CENDX) with regard to operative morbidity and stroke prevention. METHODS Forty-eight patients who underwent CENDX for RCS (RCS-OP group) were compared with a contemporaneous group of 40 patients who on at least one post-CENDX duplex ultrasonography study had a greater than 50% stenosis but did not undergo operation (RCS-NO-OP group). This latter group was drawn from 1053 follow-up duplex studies in 348 patients who underwent primary CENDX between the years 1983 and 1993. Each of these two groups was compared with a metanalysis of six key series derived from the literature. RESULTS No significant differences were seen in the demographics or the incidence of risk factors between the two groups except for a higher incidence of coronary artery disease (p < 0.03) and peripheral vascular disease (p < 0.001) in the RCS-OP group. The operation-specific stroke rate was 2.1%, and the 30-day mortality was also 2.1%. Symptomatic RCS was the indication in 56% of cases. Important anatomic differences were found between groups. The duplex/arteriographic degree of stenosis was greater than 90% in 75% of the patients in the RCS-OP group, whereas only 10% of the patients in the RCS-NO-OP group had greater than 80% stenosis, most being in the 50% to 80% range. An unexpected finding was the sudden progression to occlusion in 10 (25%) of 40 in the RCS-NO-OP group, with 2 (5%) of 10 of the occlusions presenting as unheralded strokes. Overall, a stroke without an antecedent transient ischemic attack occurred in 3 (7.5%) of 40 of patients in the RCS-NO-OP group, all in patients with greater than 75% stenosis on their last documented scan preceding the stroke. CONCLUSION Given the relatively low stroke rate with surgery in the RCS-OP group (2.1%) and the higher incidence of unheralded strokes (7.5%) in the RCS-NO-OP group, a more aggressive approach may be warranted in patients with asymptomatic high-grade (> 75%) RCS, a strategy not unlike that adopted for primary CENDX.

Cardiac risk in patients undergoing carotid endarterectomy: Impact on perioperative and long-term mortality

To identify patients undergoing carotid endarterectomy who are at high risk for cardiac events and death, we studied the course of 614 patients with known risk factors who were entered into our carotid follow-up registry. Patients were divided into two groups, group I with overt coronary disease (prior myocardial infarction, angina, significant electrocardiographic abnormalities) (N = 324) and group II without overt coronary disease (N = 290). Group II patients were subdivided into groups with (IIA) (N = 206) and without (IIB) (N = 84) coronary risk factors (cigarettes, diabetes, or hyperlipidemias). Thirty-day, 5-, 10-, and 15-year life-table survival for the groups was: I = 98.5%, 68.6%, 44.9%, 36.4%, respectively; II = 100%, 86.4%, 72.3%, 54.3%, respectively; IIA = 100%, 84.8%, 66.9%, 41.5%, respectively; IIB = 100%, 90.5%, 87.9%, 87.9%, respectively. Overt coronary disease was associated with diminished 30-day (p = 0.03) and late (p less than 0.0001) survival. Risk factors in the absence of overt disease were not associated with diminished 30-day survival. Late survival up to 3 years from endarterectomy was similar in groups IIA and IIB, but later survival was diminished in group IIA. Myocardial infarction was the most frequent cause of death in all groups. Patients with overt coronary disease are at high risk for late cardiac events and death. Patients without overt disease are at less risk than those with overt disease, and in the absence of overt disease, those without are at less risk than those with risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)