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Biomedical subjects

B L Thiele

Publications and source records attributed to B L Thiele.

At least 19 recordsLinked to original sources
PubMed1994

Validation of air plethysmography, photoplethysmography, and duplex ultrasonography in the evaluation of severe venous stasis.

PURPOSE: The purpose of this study was to validate the diagnostic capabilities of the most commonly used noninvasive modalities for evaluation of chronic venous insufficiency. METHODS: Twenty limbs in 20 patients were studied with air plethysmography (APG), photoplethysmography (PPG), and duplex ultrasonography. Ten limbs (group 1) were clinically without any venous disease. Group 2 consisted of 10 limbs with severe, class 3 venous stasis. Duplex ultrasonography, complemented with Doppler color-flow imaging was used to examine the superficial and deep venous systems to identify reflux. RESULTS: Ultrasonography identified deep venous reflux in eight of 10 limbs in group 2. Severe superficial reflux was identified in the two remaining limbs. Seven limbs with deep reflux also demonstrated severe superficial reflux. Superficial venous reflux was identified in one leg in group 1. APG accurately separated normal limbs from those with reflux. Parameters that were significantly different (p < 0.05) between the two groups were the venous filling index, (group 1 = 1.37 +/- 1.16 ml/sec, group 2 = 29.5 +/- 6.2 ml/sec.), venous volume (group 1 = 107 +/- 10.1 ml, group 2 = 220 +/- 22.5 ml), ejection fraction (group 1 = 52.5% +/- 2.3%, group 2 = 32.5% +2- 4.6%), and residual volume fraction (group 1 = 21.4 +/- 2.0%, group 2 = 52.1% +/- 2.5%). PPG refill times were significantly shortened in group 2 versus those of group 1 (6.4 +/- 0.89 sec vs 20.2 +/- 1.1 sec). The sensitivity of PPG refill times to identify reflux was 100%, but the specificity was only 60%, whereas the sensitivity and specificity for the residual volume fraction was 100%. The venous filling index was able to identify reflux and determine whether only superficial reflux was present with a sensitivity of 100% and a specificity of 90%. The kappa coefficient of agreement between duplex scanning and APG was 0.83, whereas between duplex and PPG it was only 0.47. CONCLUSION: APG accurately identifies limbs with and without venous reflux when compared with duplex ultrasonography. APG is a better method of evaluating clinically significant venous reflux than PPG. PPG is a sensitive method of detecting reflux, but the specificity is poor, and PPG refill times cannot accurately predict the location of reflux. The combination of APG and duplex ultrasonography provides the best means of assessing venous reflux.

Adolescent↗
PubMed1994

Relative risks of limb revascularization and amputation in the modern era.

A retrospective review of 266 patients undergoing infrainguinal revascularization for limb salvage and/or major amputation (transmetatarsal, below-knee or above-knee) from 1984 to 1990 was conducted to determine comprehensive procedure-specific 30-day operative morbidity and mortality rates. Some 211 patients underwent 295 infrainguinal vascular reconstructions (195 primary and 100 secondary reconstructions). There were 122 major amputations in 98 patients (29 above-knee, 70 below-knee and 23 transmetatarsal). Most amputations were performed in patients with unreconstructable vascular disease, including 39 patients (41 extremities) with failed infrainguinal reconstruction. Procedure-specific morbidity and mortality rates were 48 and 2% for primary revascularization, 35 and 2% for secondary revascularization and 37 and 4%, for amputation, respectively. The difference in mortality between revascularization and amputation approached but did not achieve statistical significance. Cardiac, graft and wound complications were the major causes of morbidity in all groups. Nine of the 12 deaths were of cardiac etiology. Revascularization can be performed in almost all patients with advanced limb ischemia, with a mortality rate equivalent to, or perhaps lower than, that of amputation. When limb amputation is required, it can be performed with a mortality rate remarkably lower than that described in the older literature.

Acute Disease↗
PubMed1994

Current applications of duplex ultrasonography and color Doppler imaging.

Duplex ultrasound is a noninvasive method of evaluating the function of the systemic arteries and veins. In this review, the physical principles of duplex ultrasonography are discussed and compared to other available noninvasive tests. The clinical applications of duplex ultrasound and color Doppler imaging are reviewed and diagnostic criteria stated. Newer and more controversial applications of duplex ultrasound are presented.

Blood Vessels↗
PubMed1994

Prediction of postoperative complications after elective aortic surgery using stepwise logistic regression analysis.

Perioperative risk factors that contribute to postoperative morbidity have been identified for various forms of vascular disease, but it is not clear to what degree each type of disease contributes to morbidity when these diseases are seen in combination. We used stepwise logistic regression analysis to determine the relative importance of 25 risk factors in predicting postoperative complications in 100 consecutive patients undergoing elective intra-abdominal aortic surgery (59% aneurysmal disease, 37% occlusive disease, 26% renal artery lesions). Thirty-one patients developed postoperative complications, including three deaths. The most common complication was deterioration in renal function (17 patients, 24% of those at risk) followed by the need for prolonged endotracheal intubation (> 48 hours, 8%). All other events occurred uncommonly (4% or less). Stepwise logistic regression demonstrated four criteria that were significantly associated with complications. In descending order of importance these were: renal artery occlusive disease, intraoperative blood replacement, the preoperative APACHE II score, and a history of heavy smoking. Since both physiologic status and comorbid conditions contribute to morbidity and costs of elective vascular surgery, outcome studies must be adjusted to account for these preoperative characteristics. Additionally, since two-thirds of patients who have renal artery occlusive disease develop complications that prolong hospitalization, our current methods of protecting the kidney during ischemia should be improved to potentially reduce this cause of morbidity.

Adult↗
PubMed1994

Successful identification of acute renal allograft rejection with duplex ultrasonography.

Duplex ultrasonography has met with variable accuracy in identifying acute renal allograft rejection. These published studies have focused on using mathematical indices. We have applied duplex ultrasonography differently by insonating the site of rejection, i.e. renal cortex, to identify by subjective analysis the changes of the velocity spectral patterns. This subjective analysis method was compared to the mathematical indices of diastolic/systolic ratio and pulsatility index in 126 episodes of clinical acute renal allograft rejection which all had biopsy correlation. This present study represents the largest published experience with duplex ultrasonography and renal transplant rejection. Subjective analysis of velocity spectral patterns (SUBJ) resulted in sensitivity of 87%, specificity of 94% and overall accuracy of 88%. This technique was statistically better than the diastolic/systolic ratio (DSR) sensitivity of 40%, specificity of 72% and overall accuracy of 49%, or the pulsatility index (PI) sensitivity of 47%, specificity of 75% and overall accuracy of 55%. The superior results of the subjective analysis technique of duplex ultrasonography to identify acute renal allograft rejection suggests that this diagnostic approach has sufficient accuracy to avoid invasive allograft biopsies.

Acute Disease↗
PubMed1993

Influence of age on venous physiologic parameters.

PURPOSE: The incidence of deep venous thrombosis increases significantly with age. Attempts to explain this association have failed to identify factors that could be contributory. We hypothesized that age-related changes in venous physiologic parameters might contribute to an increased risk of deep venous thrombosis. METHODS: Air plethysmography was used to measure a number of physiologic parameters in two sets of patients. Group A consisted of 17 subjects (33 limbs), age range 23 to 40 years. Group B consisted of 11 subjects (22 limbs), age range 60 to 83 years. No subject in either group had peripheral vascular disease or a history of deep venous thrombosis. Parameters measured were venous volume, venous filling index, ejection volume, ejection fraction, residual volume fraction, and outflow fraction. RESULTS: Venous volume and ejection fraction were significantly reduced in Group B compared with Group A. Residual volume fraction was significantly increased in Group B compared with Group A. There were no statistically significant differences in outflow fraction, venous filling index, or ejection fraction between the two groups. CONCLUSIONS: These results suggest that the efficiency of the calf muscle pump diminishes with increasing age, possibly contributing to the increased incidence of deep venous thrombosis in the elderly.

Adult↗
PubMed1992

Delayed postoperative nonembolic neurologic deficit after left internal carotid endarterectomy in presence of known contralateral carotid artery occlusion.

Neurologic sequelae are known complications of carotid endarterectomy. The current overall perioperative stroke rate is 2-5% (1,2). The incidence of perioperative morbidity and mortality is increased in certain patient subgroups, including neurologically unstable patients and patients who have known contralateral common or internal carotid artery occlusion (3-9). We present the case of a patient who had known total right carotid artery occlusion and a known previous right cerebrovascular accident who sustained a contralateral deficit after a left internal carotid thromboendarterectomy with vein patch angioplasty.

Journal Article↗
PubMed1992

Evaluation of celiac and mesenteric vascular disease with duplex ultrasonography.

A retrospective study of 25 patients was performed to evaluate the applicability of duplex ultrasonography to the celiac and superior mesenteric circulation. Lateral contrast aortograms were compared to the pulsed-Doppler spectral data from duplex examinations in fasting subjects. A significant correlation was identified between the celiac-aortic diastolic ratio and the degree of stenosis measured angiographically, but such a relationship could not be established for the superior mesenteric artery. These data suggest that duplex ultrasonography may not be a reliable screening test for mesenteric vascular disease.

Angiography↗
PubMed1991

Arterial reconstruction of the pancreatic allograft for transplantation.

The shortage of organs is particularly acute in whole pancreas transplantation, because the liver and pancreas often share a common arterial supply, making combined procurement of both organs difficult. A previously described technique of simultaneous whole liver and pancreas procurement depended on "classic" hepatic arterial anatomy, which is present just over half the time. We describe herein our experience with three Y-reconstructions of the splenic and superior mesenteric arteries of the pancreatic allograft using donor allograft internal and external iliac arteries. In situ Doppler ultrasound examination of the pancreatic allograft after surgery demonstrated a patent reconstruction without evidence of stenosis or turbulent flow patterns. We believe this reconstruction is a safe, alternative method to provide arterial flow to the whole donor pancreas.

Humans↗
PubMed1990

The vascular laboratory. Standards and certification.

The diversity of testing methodologies and reporting practices has necessitated that standards be defined for both performance of testing as well as interpretation and reporting of results. The guidelines to be used for the noninvasive diagnosis of extracranial vascular disease and the rationale for their use are presented. Emphasis is placed upon realistic diagnostic features that have clinical relevance and the use of testing methods that can identity these features. Further developments in this field, particularly those addressing the overall performance of vascular diagnostic laboratories, are to be defined by a multiprofessional inter-societal commission in the near future. It is anticipated that a voluntary accreditation process will insure high quality of testing.

Blood Flow Velocity↗
PubMed1990

Wound complications of autogenous subcutaneous infrainguinal arterial bypass surgery: predisposing factors and management.

To identify factors predisposing to wound infection and necrosis complicating in situ or other subcutaneous autogenous lower extremity vein bypass procedures, we retrospectively analyzed all such cases performed in our hospital between July 1983 and July 1988. Among 163 subcutaneous autogenous bypass grafts, wound complications developed in 28 (17%). According to progressive depth of involvement as defined in the text, 10 patients had grade I complications, six had grade II, and 12 had grade III complications with threatened or actual graft exposure. Factors significantly associated with wound morbidity were female gender, chronic steroid therapy, in situ bypass grafting, use of continuous incision (all p less than or equal to 0.05, chi square); diabetes mellitus, ipsilateral limb ulcer, limb salvage indication (all p less than 0.01); and bypass grafting to the dorsalis pedis artery (p less than 0.02). A logistic regression analysis identified four factors (in situ bypass grafting, steroid therapy, ipsilateral ulcer, and dorsalis pedis bypass grafting) that predicted a cumulatively increasing risk of wound complications, and in whose absence wound complications were rare. Grade I and II complications responded to standard regimens of wound care and intravenous antibiotics without loss of any graft or limb. In spite of aggressive efforts to provide secondary soft tissue coverage, grade III complications led directly to four major amputations and one death. Measures to prevent these morbid sequelae must include preoperative control of infection in the ischemic foot and meticulous attention to operative technique.

Aged↗
PubMed1990

Combined aortic and visceral arterial reconstruction: risks and results.

The indications, morbidity, and efficacy of combined reconstruction of the abdominal aorta and visceral arteries (renal and superior mesenteric; excluding suprarenal aortic aneurysms) were analyzed retrospectively in 29 consecutive patients who underwent surgery from June 1984 through February 1990. Seventeen men and 12 women ages 32 to 76 years (mean, 66 years) were studied. Follow-up was complete in all patients to either death or calendar year 1989 to 1990 (mean, 31.9 months; range, 2 to 66 months). All patients underwent bypass of angiographically proven severe lesions of one renal artery (19 patients), both renal arteries (8 patients), or the superior mesenteric artery and renal arteries (2 patients), in concert with synthetic distal aortic replacement for occlusive disease (10 patients) or aneurysm (19 patients). Indications for renal artery repair included severe hypertension in 13 patients, ischemic renal insufficiency in 8 patients, and lesion morphology alone in 8 patients. Operative mortality rate was 3 of 29 (10.3%), and each death was the result of multisystem organ failure. Nonfatal complications occurred in 11 of the 26 survivors (42%), and this group differed significantly from the uncomplicated 15 patients only in having a higher mean preoperative serum creatinine (2.5 +/- 1.1 mg/dl vs 1.6 +/- 0.9 mg/dl, p = 0.04, t test). The mortality rate of patients with preoperative serum creatinine greater than or equal to 2.0 mg/dl, was 15.4% (2/13 patients), compared to 6.2% (1/16) in patients with creatinine less than 2.0 mg/dl. Three late deaths occurred (2 stroke, 1 cancer). Hypertension control improved in 64% of patients overall, and in 7 of 9 patients whose major operative indication was renovascular hypertension. Renal function remained stable or improved in 12 of 15 patients (80%) with renal insufficiency, but 3 patients progressed to require dialysis. Long-term graft patency was demonstrated by angiography or on duplex scan in all studied survivors (21 patients). Although operative risks are clearly increased compared to less complex vascular procedures, careful patient selection and management will yield a favorable outcome in most patients with such combined lesions.

Adult↗