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Biomedical subjects

H D Berkowitz

Publications and source records attributed to H D Berkowitz.

At least 37 records · Page 2Linked to original sources
PubMed1987

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↗
PubMed1987

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↗
PubMed1987

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↗
PubMed1986

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↗
PubMed1986

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↗
PubMed1985

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↗
PubMed1984

Noninvasive techniques in the assessment of lower-extremity arterial occlusive disease. The advantages of proximal and distal thigh cuffs.

We studied 209 limbs angiographically and noninvasively to determine whether measurements of upper-thigh (UT) and lower-thigh (LT) segmental pressures (four-cuff technique), combined with segmental pulse-volume recordings (PVRs), offered any advantage over the standard single-thigh cuff (three-cuff technique) and PVR in the diagnosis of aortoiliac (AI) and superficial femoral artery (SFA) occlusive disease. Angiographic stenosis of 50% or greater and occlusions were considered to be hemodynamically significant lesions in this study. In the absence of SFA disease, sensitivity to AI disease was high (96%) and not significantly different using three- or four-cuff measurements. However, in the presence of SFA-segment disease, four-cuff measurements, both with and without PVR, were significantly more sensitive to AI disease (100%) and more specific for a normal AI segment (76%) than the three-cuff, PVR technique. Plethysmography alone was most sensitive to SFA disease (90%), even in the presence of AI disease, and sensitivity was not improved by additional segmental pressure measurements. The four-cuff system enhances the physician's ability to diagnose AI disease in the presence of SFA lesions, while PVR is most useful in detecting SFA lesions in the presence of AI disease.

Angiography↗
PubMed1982

Hypertrophic osteoarthropathy as indication of aortic graft infection and aortoenteric fistula.

Diagnosis of an infected bifurcation graft or aortoenteric fistula can be extremely difficult, and delay in diagnosis may lead to the lethal complication of a ruptured aortoenteric fistula. Hypertrophic osteoarthropathy limited to the lower extremities was the initial symptom of aortoenteric fistula in two of our patients with infected aortic bifurcation grafts. Review of the literature discovered six additional patients with a similar diagnosis, indicating its possible value as an early diagnostic sign of aortoenteric fistula.

Aorta↗
PubMed1982

Treatment of acute peripheral arterial and graft thromboses with low-dose streptokinase.

Seventeen patients with acute peripheral arterial or graft occlusion were treated with local low-dose intra-arterial streptokinase. The series includes eight patients with native vessel occlusion, six patients with vein graft occlusion, two patients with prosthetic graft occlusion, and one patient with renal allograft artery occlusion. The duration of occlusion prior to streptokinase therapy varied from 2 hours to 5 weeks. The treatment was successful in 14 of the 17 instances. In conjunction with the successful thrombolytic therapy, percutaneous transluminal angioplasty was performed subsequently in 10 of the patients and reconstructive surgery in three. One major and five minor hemorrhagic complications occurred and were considered to be secondary to the streptokinase therapy. In follow-up of up to 9 months, 11 of the 14 successfully treated patients continued to have a good result, without any indication of recurrent arterial occlusion. Two patients have died of causes unrelated to thrombolytic therapy and one patient required bypass grafting for recurrent thrombosis. None of the successfully treated patients lost a limb. Of the three patients in whom thrombolysis was unsuccessful, two required amputation. Local intra-arterial low-dose streptokinase appears to be a promising alternative to immediate operative treatment in carefully selected cases of arterial occlusion. Definitive treatment of the underlying cause of the thrombus usually is required and changes of success may be enhanced by the thrombolytic therapy.

Adult↗
PubMed1981

Transluminal angioplasty of the iliac and femoral arteries: follow-up results without anticoagulation.

With the advent of the angiographic balloon catheter, transluminal angioplasty has become a more effective procedure for the alleviation of symptoms of peripheral ischemia. In the past two and a half years we have performed this procedure on over 208 iliac and femoral arteries. One hundred twenty iliac arteries were dilated. Of these, 86% remained patent at one year and 83% at two years. Eighty-eight femoral arteries were dilated. Of these, 75% remained patent at one year and 67% at two years. These vessel survival rates are slightly less than those following surgery. However, the morbidity from transluminal angioplasty is very low and the mortality is essentially zero.

Adult↗
PubMed1981

Value of routine vascular laboratory studies to identify vein graft stenosis.

Thirty-three stenotic lesions were found in 30 vein grafts (17 femoral-popliteal, 13 femoral-tibial) 3 months to 8 years postoperatively--77% appeared within 1 year of surgery. Seventeen (57%) of the patients presented with normal distal pulses, and a similar number were asymptomatic. Only eight (26%) presented with unequivocal clinical evidence of graft stenosis based on decreased pulses and return of ischemic symptoms. Forty percent were completely asymptomatic with normal distal pulses. The mean postoperative ankle systolic pressure index (ASPI) was 0.83 +%- 0.03 (SEM); it fell to 0.57 +/- 0.04 (SEM) when stenosis developed. The peripheral vascular laboratory measurements were the key factor influencing the decision for repeat arteriography in many of these patients and reinforced the need for a repeat arteriogram when the clinical diagnosis was unclear. Early diagnosis of vein graft lesions prior to graft occlusions allowed 24 of 30 of these stenotic grafts to be treated primarily by percutaneous transluminal angioplasty (PTA); 80% remained patent 24 months after PTA. Since most vein graft stenoses can be treated by such a simple, nonoperative technique (PTA), every effort should be made to diagnose and treat lesions prior to graft occlusion. Our experience indicates that frequent vascular laboratory measurements of ASPI are more sensitive then clinical examinations in detecting early vein graft stenosis.

Angioplasty, Balloon↗
PubMed1980

Diagnostic accuracy of ocular pneumoplethysmography attachment for pulse volume recorder.

The ocular pneumoplethysmography (OPG) attachment for the Life Sciences Pulse Volume Recorder (OPG-LS) is a widely distributed instrument, but no results have been published on its accuracy in diagnosing carotid artery lesions. One hundred twelve patients were studied with the OPG-LS using lateralizing criteria and a curve of ophthalmic artery systolic pressure (OAP) to brachial systolic pressure (BP) for normal carotid arteries, which served as a discriminant between normal and stenotic vessels. Two hundred nineteen carotid arteries were visualized on arteriography and percentage of diameter stenosis was measured. Lateralizing criteria by themselves gave poor diagnostic accuracy, but when combined with OAP-BP data, positive diagnosis was made for lesions having greater than 60% diameter stenosis in 89.6% of patients and 80.8% of arteries. False-positive results for 0% to 30% diameter stenotic lesions occurred in 11.1% of arteries and in 13.6% of patients.

Blood Pressure↗
PubMed1980

Balloon dilation of iliac stenosis with distal arterial surgery.

Seven patients with concomitant atherosclerotic iliac stenosis and femoral artery occlusive disease were treated with polyvinyl balloon catheter dilation of the iliac artery and subsequent distal operative arterial reconstruction. The iliac lesions were short, localized, common and external iliac stenoses and the femoral lesions were superficial femoral artery occlusions in six patients and a common femoral occlusion in another. All seven iliac stenoses were successfully dilated. Subsequent operative femoral artery reconstruction was successful in these patients, with restoration of popliteal or pedal pulses and relief of ischemic symptoms over a follow-up period of two to 14 months. One patient's femoral popliteal bypass graft thrombosed four months postoperatively.

Aged↗
PubMed1980

Treatment of stenosis of the iliac artery by balloon catheter dilation.

Percutaneous balloon catheter angioplasty appears to be an effective method of treatment for localized iliac artery stenosis. Results of our experience demonstrate that it can be accomplished with an acceptable morbidity in carefully selected patients and can be done and even repeated with minimal inconvenience to the patient.

Arterial Occlusive Diseases↗
PubMed1979

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↗
PubMed1978

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↗