Carotid endarterectomy: vindicated but ....
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Carotid Stenosis↗
Biomedical subjects
H D Berkowitz
Publications and source records attributed to H D Berkowitz.
A technique for suturing anastomoses involving calcified vessels.
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Calcinosis↗
Reversed vein graft stenosis: early diagnosis and management.
Conscientious surveillance of intrainguinal bypass grafts is mandatory to detect vein graft stenoses, which, if uncorrected, can lead to graft occlusion. It is now widely accepted that noninvasive vascular laboratory studies are the best way to detect these lesions. However, controversy still exists over treatment, specifically whether balloon angioplasty is an acceptable substitute for surgery (patch angioplasty or short jump grafts) in the treatment of these lesions. We have always favored balloon angioplasty as primary treatment and have summarized our experience with treating 72 stenotic reversed femoropopliteal and femorotibial vein grafts, which represent 12% of 521 bypass grafts performed at our institution. Prosthetic and in situ grafts are specifically excluded from this report, as well as occluded grafts, found to have stenotic lesions after lytic therapy. The most common stenotic lesion occurred within 4 cm of the proximal anastomosis (29/72 = 40%). The other sites were near the distal anastomosis (7/72 = 10%), and in the middle of the graft (15/72 = 12%). Eighty-one percent (58/72) of the lesions were treated initially by balloon angioplasty with a 31% recurrence. Twenty-nine percent of the 14 grafts treated surgically by vein patch angioplasty or short jump grafts experienced recurrence. Overall 61% (44/72) of the stenotic grafts were treated by balloon angioplasty alone. The 5-year life-table assisted primary patency after correction of the stenotic lesion was 61%. The patency of the grafts from the time of initial bypass surgery, however, was 80%. Location of the stenosis within the graft was a major determinant of patency. Lesions in the proximal graft, proximal anastomosis, and distal graft taken as a group had significantly better patency than the midgraft and distal anastomotic lesions (5-year patency, 65% vs 48%, p less than 0.001 log rank test). We continue to recommend balloon angioplasty as primary therapy for vein graft stenosis except for those occurring in the midgraft and distal anastomosis. Fortunately, this group accounts for only 36% of lesions seen with reversed veins. Recurrent stenosis after balloon angioplasty should be repaired surgically.
Aged↗
Magnetic resonance angiography of peripheral runoff vessels.
Recent improvements in magnetic resonance imaging techniques have made magnetic resonance angiography (MRA) a very useful adjunct to invasive angiography. Fifty-five limbs in 51 patients with occlusive peripheral vascular disease were studied with both MRA and contrast arteriography. The magnetic resonance and contrast arteriograms were read by radiologists and surgeons and separate interventional plans were based on each study. The MRA findings differed significantly from those of conventional arteriography in 26 limbs (48%). In every case MRA visualized all of the same vessels and hemodynamic stenoses seen on the contrast arteriogram. In 48% of the cases, however, MRA revealed additional findings. Thus the discrepancies in the two studies were always the result of the failure of the arteriogram to reveal all of the patent vessels seen on MRA. The additional information provided by MRA resulted in alteration of the interventional plan in 11 cases (22%). In nine cases (18%) target vessels suitable for use in a limb-salvage procedure were identified by MRA, although they had been missed by conventional arteriography. In all of these cases, intraoperative arteriograms confirmed the suitability of these vessels for use in technically successful bypass procedures. In two cases (4%) additional information provided by MRA identified a target runoff vessel for bypass grafting that proved to be a better alternative than the one that would have been chosen on the basis of contrast arteriography.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Thoracoabdominal aneurysm resection after previous infrarenal abdominal aortic aneurysmectomy.
Thoracoabdominal aneurysms in 51 patients were repaired over 5 years ending in February 1991. Fourteen (27%, 14 of 51) patients had a prior infrarenal aneurysm resection (PRA); their data are analyzed separately. The average age of patients who had undergone PRA was 67 years (range: 56 to 86 years). The mean aneurysm diameter was 8.6 cm (range: 5 to 12 cm), and the mean time interval between initial aneurysm surgery and subsequent resection of the thoracoabdominal aneurysm was 8.5 years (range: 2 to 17 years). Three patients in the PRA group were operated on emergently, two because of clinical evidence of rupture; the other patients underwent elective repair. Early mortality (30 days) in the PRA group was significantly related to age (72 years or older versus younger than 72 years: 75% versus 10%, p = 0.04), proximal extent of aneurysm (above diaphragm versus below diaphragm: 50% versus 0%, p = 0.05), ruptured aneurysm (ruptured versus nonruptured: 100% versus 16%, p = 0.06), and a cardiac history of myocardial infarction (57% versus 0%, p = 0.03), congestive heart failure (66% versus 0%, p = 0.01), or arrhythmia (80% versus 0%, p = 0.005). Similar results were seen with the entire group of patients with thoracoabdominal aneurysms except that the proximal extent of the aneurysm was not related to mortality. These results demonstrate that thoracoabdominal aneurysm resection after prior infrarenal aneurysmectomy is not associated with increased mortality or morbidity.
Age Factors↗
Femoropopliteal angioplasty. Factors influencing long-term success.
Prospective data was recorded on 217 percutaneous transluminal angioplasty (PTA) procedures performed in the superficial femoral and popliteal arteries over an 8-year period. After the initial procedure, patients were followed with serial noninvasive studies and, in 71 patients, repeat angiography. The mean follow-up period was 7 years (range, 2-11 years). Standard life-table survival analysis was used to assess the factors potentially affecting long-term outcome. Excluding an initial technical failure rate of 10%, overall patencies at 1, 3, and 5 years were 81%, 61%, and 58%, respectively. After the first year, the prognosis (i.e., failure rate) appears to be linear over the long term (i.e., up to 10 years). Factors negatively influencing long-term patency include the presence of diabetes mellitus, diffuse atherosclerotic cardiovascular disease, or threatened limb loss. Technical factors correlated with failure include lesion length, moderate eccentricity, and a poor post-PTA appearance.
Angioplasty, Balloon↗
Plug technique for controlling lumbar and intercostal bleeding during aortic surgery.
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Aorta↗
Late failure of reversed vein bypass grafts.
Late failure of reversed vein bypass grafts is preceded by the appearance of stenotic lesions, which progress to total occlusion. These lesions appear either as intrinsic graft lesions or as new arteriosclerotic lesions in contiguous arteries. The present study summarizes the University of Pennsylvania experience with these lesions in 521 vein grafts inserted from 1979 to 1985. The grafts were grouped according to the site of the distal anastomosis; 231 above-knee popliteal (FP AK), 171 below-knee popliteal (FP BK), and 119 tibial (FT). The overall incidence of stenotic lesions was essentially identical with the three grafts (21%), but the relative incidence of intrinsic graft to arterial lesions was higher with the more distal grafts. The most common graft lesions developed adjacent to the proximal anastomosis, which is the narrowest part of a reversed vein graft. The popliteal artery was the most common site of outflow stenosis. There was negligible incidence of tibial lesions. The most common inflow arterial lesion was located in the common femoral and iliac arteries. The superficial femoral artery (SFA) was a rare site of inflow stenosis, even though it was at risk because 96 grafts originated from the SFA or popliteal artery. Sixty-seven per cent of the graft and 52% of the arterial lesions were treated successfully by percutaneous transluminal angioplasty; the rest had minor surgical revisions. This resulted in a 19%, 10%, and 9% improvement in 5-year patency for the FT, FP BK, and FP AK bypasses. These results justify an aggressive policy of graft surveillance to identify and treat stenotic graft lesions before graft occlusion.
Graft Occlusion, Vascular↗
Renovascular hypertension in children. Surgical repair with special reference to the use of reinforced vein grafts.
Surgical correction of renovascular hypertension in children is especially challenging because there is high incidence of bilateral renal artery lesions and stenosis of the abdominal aorta. Seventeen patients with severe hypertension, whose ages ranged from 2 to 16 years (mean 10.2 years), had surgical repair of these lesions from 1974 to 1987. Twenty-nine renal artery lesions were repaired. Twelve (71%) were bilateral, five (29%) were unilateral, and eight patients (47%) had abdominal aortic lesions (midaortic stenosis). Twenty-eight saphenous vein grafts and one splenorenal graft were used to bypass the renal artery lesions. The midaortic lesions were bypassed with Dacron grafts from the superceliac aorta to the aortic bifurcation. No operative deaths occurred. Nineteen of the 28 vein grafts were reinforced with a 6 mm diameter tubular Dacron mesh to prevent aneurysmal degeneration seen in three of nine unsupported vein grafts. Follow-up arteriograms were available in 15 patients up to 11 years after operation (mean 5.0 years). There has been no aneurysmal dilatation in the 19 mesh-supported grafts. The ratio of vein graft diameter to the diameter of the native aorta was 1.25 +/- 0.38 (+/- standard deviation) in unsupported grafts and 0.65 +/- 0.09 in mesh-supported grafts, representing a 92% increased diameter in the unsupported grafts. Three vein grafts (10.3%) required percutaneous transluminal angioplasty for late postoperative vein graft stenoses, but no stenotic lesions have developed at the aortic suture lines. One graft occluded 7 years postoperatively after replacement of an aneurysmal vein graft, and one early postoperative graft occlusion occurred, for a graft failure rate of 7%. Seventy-six percent of patients (13 of 17) are normotensive without medication, and 24% (4 of 17) are considered improved with hypertension controlled with a lower dose of medication. Our results attest to the safety and efficacy of this complicated surgery. Saphenous veins, supported by external Dacron mesh, appear to be a suitable graft material for renal reconstruction in this population.
Adolescent↗
The midaortic syndrome: diagnosis and treatment.
The midaortic syndrome is an unusual entity seen in children and adolescents. It is characterized by severe narrowing of the abdominal aorta with progressive involvement of the renal and visceral branches. Eleven patients (aged 5 months to 15 years) suspected of having midaortic syndrome were examined preoperatively and postoperatively. All patients had hypertension and were examined with midstream aortography. All aortograms showed a smooth, segmental stenosis of the abdominal aorta and severe bilateral proximal renal artery stenosis. In three patients, percutaneous transluminal angioplasty of the renal artery was attempted, two preoperatively and one for a postoperative stricture. None showed long-term success, presumably due to the progressive nature of the disease. Grafts were surgically placed in ten patients and produced successful results in nine.
Angioplasty, Balloon↗
Heparin-induced platelet activation in sixteen surgical patients: diagnosis and management.
Heparin-induced platelet activation (HIPA) is a syndrome associated with thrombocytopenia, intravascular thrombosis, and arterial emboli. We have evaluated 16 patients for presumed HIPA because of the occurrence of thrombocytopenia or a new thrombotic complication during heparin therapy. In this group, 16 thrombotic events occurred in 10 patients with a mortality rate of 18.8%. Diagnosis was confirmed in vitro by the demonstration of at least 20% platelet aggregation and/or 6% 14C-serotonin release after heparin (0.1 to 3 U/ml) was added to a mixture of patient platelet-poor plasma (PPP, two parts) and aspirin-free donor platelet-rich plasma (PRP, three parts). After heparin was discontinued, seven patients continued to have HIPA in their own PRP although it could no longer be observed in donor PRP. Iloprost, a potent prostacyclin analog that reversibly inhibits platelet activation, completely prevented HIPA and release in all of nine patients. Aspirin, an irreversible cyclooxygenase inhibitor, failed to prevent HIPA in four of these nine patients. In conclusion, HIPA is associated with an extremely high morbidity and mortality rate. Evaluation of the patients' PRP in response to heparin may improve the diagnostic sensitivity of this assay. Aspirin does not reliably prevent HIPA, which suggests participation of thromboxane-independent pathways. Thus, if further exposure to heparin is unavoidable, a more effective platelet inhibitor such as iloprost is required to reliably prevent in vivo HIPA.
Adult↗
Improved patency in reversed femoral-infrapopliteal autogenous vein grafts by early detection and treatment of the failing graft.
One hundred two femoral-infrapopliteal bypasses, in which reversed autogenous saphenous vein grafts were used, were performed from January 1978 to July 1984, in 94 patients with severe claudication (14%) or threatened limb loss (86%). Follow-up examinations at 3-month intervals during the first 18 months and at 6-month intervals thereafter were performed to document the return of ischemic symptoms or loss of peripheral pulses. Ankle pressure index and pulse volume recordings were also measured. A decrease in ankle pressure index equal to or greater than 0.2 or a pulse volume recording decrease of 5 mm or more with or without confirmatory symptoms were indications for repeat arteriography. Twenty-two primary graft or anastomotic stenoses were discovered in 19 grafts during follow-up. Seventy-eight percent of these lesions were treated primarily by percutaneous transluminal angioplasty and the remainder were treated by short proximal interposition grafts or patch graft angioplasty. Twenty-five grafts occluded during follow-up and all of these were considered to have failed for purpose of life-table analysis. Stenotic lesions, which were corrected before occlusion, were listed as continuously patent under secondary patency and as failed under primary patency life-table analysis. The secondary graft patency rate was 70% at 5 years, which was significantly higher (p less than 0.01) than the primary patency rate (47%), which was obtained without intervention. This 23% differential represents graft salvage achieved by careful surveillance and is reflected not only by improved patency but also by high limb salvage rates (86%) observed at 5 years.
Constriction, Pathologic↗
Carotid endarterectomy in patients with heparin-induced platelet activation: comparative efficacy of aspirin and iloprost (ZK36374).
Patients with heparin-induced platelet activation who are reexposed to heparin may have recurrent thrombocytopenia, intravascular thrombosis, arterial emboli, or sudden death. To permit carotid endarterectomy in two patients with confirmed heparin-induced platelet activation, we compared the efficacies of aspirin and iloprost, a stable analogue of prostacyclin, in preventing heparin-induced platelet activation. In the first patient, although aspirin prevented both in vitro heparin-induced platelet aggregation (70% without and 7.5% with aspirin) and 14C serotonin release (48% without and 0% with aspirin), intraoperative administration of heparin resulted in an increase in plasma levels of platelet factor 4 from 8 to 260 ng/ml and beta-thromboglobulin levels from 29 to 39 ng/ml. In addition, the circulating platelet count decreased from 221,000 to 174,000 microliters, and 15% spontaneous platelet aggregation was observed. Fortunately, fibrinopeptide A levels remained less than 10 ng/ml intraoperatively, and no thrombotic complications occurred. In the second patient, aspirin did not prevent heparin-induced platelet aggregation in vitro (65% without and 41% with aspirin); however, iloprost (0.01 mumol/L) prevented both in vitro heparin-induced platelet aggregation (59.5% without and 0.0% with iloprost) and 14C serotonin release (56.7% without and 0.0% with iloprost). Therefore, a continuous infusion of iloprost was begun before administration of heparin and was continued until 20 minutes after reversal of heparin with protamine. After intraoperative administration of heparin, plasma levels of platelet factor 4 increased from 19 to 200 ng/ml, and beta-thromboglobulin levels increased from 56 to 76 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Magnetic resonance spectroscopy of normal and diseased muscles.
Phosphorus magnetic resonance spectroscopy (P MRS) affords and innovative approach to the study of the oxidative enzyme content of normal and diseased muscles. Examples of the evaluation of the enzyme content of normal muscles by an exercise protocol are provided. The protocol affords a hyperbolic work/cost profile, the Vmax of which is calculated by the reciprocal plots giving the enzyme content and the "effective Michaelis constant" with an evaluation of the resting metabolism. This steady state protocol clearly illustrates enzyme adaptation, on the one hand, and tissue atrophy particularly in the case of tissue injury, Duchenne's dystrophy, and genetic deletion of specific enzymes, on the other hand. The method is rapid, safe, and affords a quantitative evaluation of the disease process and possibilities for following appropriate therapies. So far, approx 1000 examinations of normal and diseased human limbs have been carried out in our laboratory in over the past four years.
Acidosis↗
31P nuclear magnetic resonance spectroscopy: noninvasive biochemical analysis of the ischemic extremity.
The biochemical effects of peripheral vascular disease on skeletal muscle have not been characterized precisely because of the lack of satisfactory noninvasive analytic methods. 31P nuclear magnetic resonance (NMR) spectroscopy was used to measure the high-energy phosphate compounds, phosphocreatine (PCr) and adenosine triphosphate, as well as metabolic byproducts, such as inorganic phosphates (Pi) and phosphate monoesters in calf muscles of 214 limbs with peripheral vascular disease. Intracellular pH was also measured. The NMR index (Pi[PCr + Pi]) was used to quantitate the impairment of oxidative phosphorylation as a result of ischemia. Studies done at rest documented the impairment of oxidative metabolism only in limbs with severe ischemia (ankle-brachial pressure index (API) less than 0.4). Exercise resulted in a significant elevation of the NMR index in all limbs and the rate of return of this value toward normal following exercise was prolonged even in limbs with moderate ischemia (0.4 less than or equal to API less than or equal to 0.9). Correlation of 31P NMR parameters with arteriograms showed that infrapopliteal occlusions resulted in prolonged recovery times only when the superficial femoral artery was occluded and emphasized the metabolic consequences of multisegmental disease. Accumulation of glycolytic pathway intermediates correlated with the decrease in muscle cell pH observed with exercise. Despite immediate improvement in symptoms and hemodynamic parameters following revascularization, return to normal biochemical function occurs over a prolonged period of time. This study demonstrates that 31P NMR spectroscopy can successfully measure noninvasively the important phosphorus-containing compounds involved in the bioenergetics of skeletal muscle in vivo rapidly enough to permit real-time determination during exercise and recovery.
Adenosine Triphosphatases↗
Economic impact of transluminal angioplasty.
Using actual bills and follow-up records we attempted to determine the economic impact of percutaneous transluminal angioplasty. The patients selected included forty angioplasties performed early in our experience as well as forty comparable patients who had operations in the same period of time. Clinical follow-up was obtained over four years. The statistics obtained demonstrate the hospital bills for angioplasty were only 24% that of surgical treatment for femoral lesions ($1,329.00 versus $6,112.00) and 16% for iliac lesions ($1,353.00 versus $7,732.00). Using this patient sample and readily available statistical data, we calculated direct national savings for using angioplasty on all patients suitable and used a standard value of life analysis to estimate the value of lives saved by doing the less dangerous procedure. The sum total savings in the United States from using angioplasty in all suitable candidates as opposed to surgery would be $180 million per year for femoral lesions and $117 million for iliac lesions. This could produce a significant savings in medical costs over the coming years.
Actuarial Analysis↗
Treatment of vein graft stenosis by balloon catheter dilation.
Percutaneous balloon catheter dilation was used to treate 12 high-grade stenoses in ten autogenous vein bypass grafts since September 1978. Four lesions occurred in femoropopliteal grafts, seven in femorotibal grafts, seven in femorotibial grafts, and one in an axillofemoral graft. Balloon catheter dilation was successful and surgery avoided in 11 of the 12 lesions. Pedal pulses were restored in eight of the ten patients, and the pulse in a femorotibial bypass graft was improved in another. Postdilation arteriography demonstrated a substantial increase in luminal diameter, and ankle pressure indexes were improved in all successful cases. The tenth had an operative correction of the stenosis. There were no complications with the procedure. Percutaneous balloon catheter dilation appears to be an effective method of treating stenosis in autogenous vein grafts and a useful alternative to surgical revision.
Arterial Occlusive Diseases↗
Femoropopliteal vein grafts for claudication. Analysis of 100 consecutive cases.
One hundred consecutive femoropopliteal venous grafts in 85 patients with claudication were followed for five years. At this time, three limbs had been amputated, approximately one quarter of the patients had expired, and 70% of the grafts in surviving patients remained patent. It is concluded that this operation does not appear to increase the risk of amputation and in fact, may lessen it. Moreover, it is associated with minimal risk and generally provides long term relief of claudication, thus enhancing the quality of life in most patients.
Adult↗