Biomedical subjects

H Groehn

Publications and source records attributed to H Groehn.

5 recordsLinked to original sources

PubMed1999

Effects of autonomic neuropathy on coronary blood flow in patients with diabetes mellitus.

BACKGROUND: C ardiac sympathetic signals play an important role in the regulation of myocardial perfusion. We hypothesized that sympathetically mediated myocardial blood flow would be impaired in diabetics with autonomic neuropathy. METHODS AND RESULTS: We studied 28 diabetics (43+/-7 years old) and 11 age-matched healthy volunteers. PET was used to delineate cardiac sympathetic innervation with [(11)C]hydroxyephedrine ([(11)C]HED) and to measure myocardial blood flow at rest, during hyperemia, and in response to sympathetic stimulation by cold pressor testing. The response to cardiac autonomic reflex tests was also evaluated. Using ultrasonography, we also measured brachial artery reactivity during reactive hyperemia (endothelium-dependent dilation) and after sublingual nitroglycerin (endothelium-independent dilation). Based on [(11)C]HED PET, 13 of 28 diabetics had sympathetic-nerve dysfunction (SND). Basal flow was regionally homogeneous and similar in the diabetic and normal subjects. During hyperemia, the increase in flow was greater in the normal subjects (284+/-88%) than in the diabetics with SND (187+/-80%, P=0.084) and without SND (177+/-72%, P=0.028). However, the increase in flow in response to cold was lower in the diabetics with SND (14+/-10%) than in those without SND (31+/-12%) (P=0.015) and the normal subjects (48+/-24%) (P<0.001). The flow response to cold was related to the myocardial uptake of [(11)C]HED (P<0.001). Flow-mediated brachial artery dilation was impaired in the diabetics compared with the normal subjects, but it was similar in the diabetics with and without SND. CONCLUSIONS: Diabetic autonomic neuropathy is associated with an impaired vasodilator response of coronary resistance vessels to increased sympathetic stimulation, which is related to the degree of SND.

Adult↗

PubMed1999

Acute calf vein thrombosis: outcomes and implications.

The purpose of this study was to define the incidence of and outcomes associated with isolated acute calf vein thrombosis (CVT). From 11/95 through 6/97, 3096 patients underwent lower extremity venous duplex testing in a hospital-based vascular laboratory in which bilateral tibial and peroneal vein imaging were standard components of the venous duplex examination. CVT was present in 118 patients (3.8%), and 339 patients (10.9%) had acute proximal deep venous thrombosis (PDVT). Patients with CVT were 56.4+/-17.2 years of age (range, 18-92). Approximately 25 per cent with CVT had cancer (n = 30). Of the 18 patients with CVT who underwent ventilation-perfusion (V/Q) lung scanning, 56 per cent (n = 10) had high-probability scans. Venous duplex reports for those with CVT recommended follow-up venous duplex examination, which was done in 60 per cent (n = 71) of patients. Of the 71 patients with CVT who underwent follow-up testing, 15.5 per cent (n = 11) progressed to PDVT. The incidence of progression to deep venous thrombosis was 25 per cent (9 of 36) in those receiving anticoagulants at the time of initial venous duplex examination versus 5.7 per cent (2 of 35) in those not receiving anticoagulants (P = 0.046). With progression to PDVT, patients were more likely to have cancer (35% versus 7.8%; P = 0.009), more likely to have high-probability V/Q scans (36% versus 6.7%; P = 0.017), and more likely to die (27% versus 1.7%; P = 0.011) during follow-up. CVT was less common than proximal deep vein thrombosis and was also associated with pulmonary embolism. Progression of CVT was an adverse clinical event associated with greater chance of pulmonary embolism and death.

Acute Disease↗

PubMed1997

Nonoperative therapy for postcatheterization femoral artery pseudoaneurysms.

Since November 1992, 160 patients were referred to the Vascular Surgery Laboratory for duplex scanning to assess whether a femoral artery pseudoaneurysm was present. Of these patients, 33 per cent (n = 53) had femoral artery pseudoaneurysms with maximal diameters ranging from 1.5 to 8.1 cm. Most pseudoaneurysms (79%; 42 of 53) followed diagnostic or therapeutic cardiac catheterization procedures. Pseudoaneurysms were treated by external compression using an ultrasound probe in 33 of these 53 patients, and thrombosis of the aneurysm was successfully induced in 76 per cent (n = 25) of those in whom nonoperative external compression therapy was attempted. Of the eight patients in whom compression was unsuccessful, three had severe pain that required cessation of compression, and femoral nerve involvement by the pseudoaneurysm was noted at surgery in two of the three. One additional patient refused a second attempt at compression due to discomfort. Of the other four failures of compression, four (50% overall) received anticoagulants during or prior to compression. In 25 patients with successful pseudoaneurysm thrombosis after external compression, none had severe pain from compression, and 40 per cent (n = 10) were on anticoagulants until or during compression. Four of the 53 (7.5%) pseudoaneurysms diagnosed in the vascular laboratory subsequently thrombosed spontaneously, and two patients (3.8%) experienced pseudoaneurysm rupture. Thrombosis of postcatheterization pseudoaneurysms can be achieved by nonoperative compression therapy in most patients. Severe pain during external compression suggests possible femoral nerve involvement by the pseudoaneurysm and is an indication for surgical therapy.

Aged↗

PubMed1996

Vena cava duplex imaging before caval interruption.

PURPOSE: Venacavograms are routinely obtained before vena cava filter placement to evaluate cava size, patency, and the presence of thrombus or venous anomalies. The objective of this study was to determine the ability of duplex ultrasonography to adequately evaluate the inferior vena cava (IVC) for size, patency, and the presence of thrombus before Greenfield filter (GF) insertion. METHODS: Duplex ultrasonographic scans were performed in 40 patients who had documented lower-extremity deep venous thrombosis diagnosed by duplex scan before GF placement. The infrarenal transverse and anteroposterior diameters of the IVC were measured, and the entire IVC was imaged for patency and the presence of thrombus or anomalies. Preoperative venacavograms were not obtained in any patients who had GFs placed in the operating room, but was performed during surgery during filter insertion. An additional 26 patients who had deep venous thrombosis and did not have caval interruption underwent IVC duplex to determine the patency and proximal extent of venous thrombosis. RESULTS: The indications for GF placement were contraindication to anticoagulation in 72.5% (29 patients); five filters were placed prophylactically; three for failure of anticoagulation; two after a complication of anticoagulation; and one before pulmonary embolectomy. The filters were placed in the operating room by surgeons in 82.5% of patients, with the remainder inserted in an angiography suite by an interventional radiologist. The ability of duplex to measure a transverse diameter of 26 mm or less had a sensitivity of 97.5%, positive predictive value of 100%, and overall accuracy of 97.5% using venacavography as the standard. Measurements of IVC diameter by duplex correlated with those based on venacavograms (r = 0.766; p < 0.001). Of the entire group of 66 IVC duplex examinations, one (1.5%) was incomplete because of technical limitations. IVC thrombus was noted by duplex in two patients who underwent GF insertion, which was confirmed with venacavography. No IVC anomalies were noted by duplex scans or venacavograms. CONCLUSION: Duplex ultrasonography is a useful and accurate method for assessment of the IVC before vena cava filter placement.

Adult↗

PubMed1996

Assessment of noninvasive lower extremity arterial testing versus pulse exam.

Palpation of pedal pulses was compared to noninvasive testing in 100 patients referred to a vascular laboratory. Subjects were 65 +/- 13 (mean +/- s.d.) years old. The right dorsalis pedis (DP) artery served as the reference artery for comparison of Doppler studies with physical examination of the pulses. Absolute Doppler pressures in the right DP were 129 +/- 50 mm Hg. The right ankle:brachial index (ABI) was 0.86 +/- 0.32. There were significant differences in ABI in those with (0.68 +/- 0.28) vs without (0.95 +/- 0.31) claudication in either extremity (p < 0.001). Rest pain was also associated with lower ABI (P < 0.04). Diabetics, hypertensives, claudicants and those with ischemic rest pain were less likely to have palpable pulses (P < 0.035). With right DP pressure >/= 118 mm Hg, 63 per cent of subjects had a palpable DP pulse, whereas 68 per cent with ABI > 0.82 had a palpable right DP. Of those (n = 35) with a right DP pressure < 118 mm Hg, only 6 per cent (n = 2) had a palpable pulse, whereas 5 per cent (2/40) with ABI </= 0.82 had palpable DP pulses. Based on these findings, it was predicted that a pulse would likely not be palpable in the left DP with a pressure < 118 mm Hg or with AB </= 0.82. The prediction based on systolic ankle pressures was correct, with 66 per cent sensitivity and 91 per cent specificity. The predication that a left DP pulse would not be palpable with AB </= 0.82 was more accurate (78% sensitive, 97% specific). Presence of a palpable DP pulse suggests the presence of a Doppler pressure >/= 188 mm Hg and ABI > 0.82. The range of ankle pressures with palpable right DP pulses was 64-220 mm Hg, whereas the range with nonpalpable DP was 42-300 mm Hg. Given the frequent disparity of pulse exam and ankle pressures, noninvasive Doppler testing may be necessary for many patients to accurately assess the vascular status of the leg.

Adult↗