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Biomedical subjects

K B Seifert

Publications and source records attributed to K B Seifert.

8 recordsLinked to original sources
PubMed1991

Myointimal hyperplasia as a result of balloon-catheter thromboembolectomy.

The balloon-tipped embolectomy catheter is widely utilized in the treatment of arterial thromboemboli, significantly improving mortality and limb salvage rates. However, early and late complications related to catheter-tip injury and balloon trauma continue to occur and compromise the results of surgical intervention. Myointimal hyperplasia is an example of an unusual late complication induced by balloon-related arterial wall trauma. Myointimal hyperplasia is a commonly recognized healing response of the arterial wall to endothelial injury but is rarely reported after balloon-catheter thromboembolectomy. The extensive nature of the injury increases the incidence of limb loss. The pathophysiologic nature of this process is reviewed, and pertinent structural details such as intimal thickening and disruption of the internal elastic lamina are presented. The pathogenesis of myointimal hyperplasia suggests guidelines for catheter use during embolectomy that may further reduce the incidence of this unusual complication.

Adult↗
PubMed1988

Bilateral upper extremity ischemia after administration of dihydroergotamine-heparin for prophylaxis of deep venous thrombosis.

Prolonged arterial spasm as a complication of ergot-containing medications has been reported since antiquity. This article describes our experience with a patient who had severe bilateral arterial spasm in the upper extremities 6 days after the initiation of a regimen of dihydroergotamine and heparin for prophylaxis against deep venous thrombosis. The spasm was refractory to oral calcium channel blocking agents and direct intraarterial infusion of tolazoline (Priscoline). However, intraarterial nitroglycerin produced a prompt and dramatic improvement in symptoms and in physical and arteriographic findings. This experience suggests that intraarterial nitroglycerin may be an appropriate first choice for ergot-induced arterial spasm.

Arm↗
PubMed1987

Pulsed Doppler frequency and carotid stenosis.

Two hundred and forty-two internal carotid arteries (ICA) were evaluated by independently interpreted arteriography and pulsed Doppler spectrum analysis using ultrasonic arteriography to evaluate the ability of peak systolic frequency (PSF) to predict the degree of internal carotid stenosis. Mean PSF in the 129 (53.3%) high grade ICA stenoses of greater than 50% diameter reduction was 6.55 +/- 0.14 (SEM) khz, while mean PSF in the 113 (46.7%) low grade (less than 50% diameter reduction) stenoses was 3.38 +/- 0.12 (SEM) kHz (P less than 0.0001). Receiver-operator characteristic (ROC) analysis revealed that PSFs of 4.5 kHz (sensitivity 87%, specificity 88%) and 5.0 kHz (sensitivity 83%, specificity 93%) were best for identifying a 50% diameter stenosis. Positive predictive value of 5.0 kHz was 93% (107/115) and negative predictive value was 82.7% (105/127). Linear regression analysis of PSF in kHz versus percentage diameter reduction yielded the equation: % stenosis = 10.7 (PSF) - 4.1 (r = 0.76). A nonlinear equation was also derived: % stenosis = 61.9 - 33.5 (PSF) + 8.7 (PSF)2 - 0.5 (PSF)3 (r = 0.77). Based on this analysis peak systolic frequency criteria measured by pulsed Doppler spectrum analysis appear to be useful for distinguishing high grade from low grade stenoses. Both the linear and nonlinear equations further suggest that PSF can more precisely quantitate the degree of ICA luminal narrowing.

Carotid Artery Diseases↗
PubMed1987

Influence of sequential pneumatic compression on postoperative venous function.

Sequential external pneumatic compression (SEPC) has been reported to decrease the incidence of acute deep venous thrombosis in postoperative patients by a direct mechanical action on the lower extremity veins and/or by inducing alterations in systemic fibrinolysis. To evaluate the effect of SEPC on venous function in the postoperative patient, pre- and postoperative venous capacitance (VC) and outflow (VO) were measured in a series of general surgical patients. In phase I, 17 limbs were evaluated in patients who had been fully ambulatory preoperatively and at complete bed rest postoperatively. VC decreased from 3.19 +/- 0.43 cc/100 cc of tissue (mean +/- standard error of the mean) preoperatively to 2.08 +/- 0.34 cc/100 cc of tissue postoperatively (p less than 0.05) and VO decreased from 87.2 +/- 10.6 cc/100 cc of tissue/min preoperatively to 58.1 +/- 8.7 cc/100 cc of tissue/min postoperatively (p less than 0.025). In phase II SEPC was begun preoperatively and continued for 24 hours postoperatively on one limb of 20 patients. SEPC prevented the decrease in VC and VO both in the pumped leg (VC-2.65 +/- 0.26 cc/100 cc of tissue preop, 2.40 +/- 0.18 cc/100 cc of tissue postop, p greater than 0.2; VO-72.3 +/- 5.9 cc/100 cc of tissue/min preop, 66.2 +/- 5.3 cc/100 cc of tissue/min postop, p greater than 0.2) and in the unpumped limb (VC-2.85 +/- 0.18 cc/100 cc of tissue preop, 2.41 +/- 0.24 cc/100 cc of tissue postop, p greater than 0.05; VO-66.1 +/- 5.2 cc/100 cc of tissue/min preop, 66.7 +/- 6.7 cc/100 cc of tissue/min postop, p greater than 0.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Continuous-wave Doppler in the intraoperative assessment of carotid endarterectomy.

A sterile 8.5 MHz continuous-wave Doppler probe was used intraoperatively to evaluate the technical result of 229 consecutive carotid endarterectomies. Primary areas of evaluation included the proximal point of plaque transection and the internal and external carotid arteries at and distal to the termination of the endarterectomy. Subjective interpretation was made of the Doppler audio signal. Signs associated with inadequate technical results were a high-frequency signal indicative of luminal narrowing with a reduction in frequency distal to the area of stenosis, absence of a Doppler signal indicating occlusion, and a weak monophasic flow signal indicating poor distal perfusion. Abnormal signals were identified in 10 internal carotid arteries (4.3%) which prompted intraoperative angiography in eight and immediate reopening of the artery in an additional two. Significant lesions were identified in seven arteries (70%). Twenty external carotid lesions (8.7%) were detected by Doppler and in 19 cases (95%) a significant stenosis or obstruction was found when the vessel was reopened. Auscultation of a continuous-wave Doppler signal with a sterile probe at operation appears to have a high positive predictive value in the identification of both internal and external carotid stenoses. It is rapid, safe, relatively inexpensive, and avoids the problems associated with routine intraoperative angiography.

Auscultation↗
PubMedDate not supplied

Advantages of continuous electroencephalographic monitoring during carotid artery surgery.

One hundred carotid endarterectomies were performed using selective shunting based on continuous electroencephalographic monitoring (CEM) for the detection of cortical ischemia. Changes associated with ischemia were loss of frequency and amplitude. The results of CEM were correlated with carotid stump pressure (CSP) measurements. Only one (4%) of the 25 patients who developed an abnormal EEG had a mean CSP greater than 50 mmHg: however, CEM was positive in only 24 (45%) of the 53 patients with a CSP less than 50 mmHg. Using EEG as a standard, no CSP criterion (50 or 25 mmHg) was sufficiently sensitive and specific to recommend its routine use (50 mmHg--96% and 61% respectively; 25 mmHg--40% and 96% respectively). Operative mortality was 1%. The three intraoperative neurologic deficits (3%), one transient and two permanent, are analyzed with respect to the operative EEG findings. In the 100 endarterectomy patients and three more undergoing carotid exploration or excision of carotid body tumor EEG changes due to anesthetic problems not associated with carotid clamping were often identified. In 48 additional endarterectomies a computerized display and disk storage of six selected EEG leads, each with a reference trace for comparison, has provided information equivalent to that from the full EEG. EEG monitoring is more accurate than CSP measurement for identifying patients who require shunting, safely dispensing with a shunt in many cases which would otherwise be shunted by standard CSP criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗