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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The practical utility of transcutaneous oxygen tension (TcPO2) has been evaluated in 22 normal subjects and in 54 patients suffering from peripheral vascular disease (PVD) at various stages (II, III, IV), to define its clinical use in the diagnosis of PVD. Basal TcPO2 values can distinguish normal subjects only from stages III and IV PVD patients. In the case of stage II PVD patients the evaluation of the half-recovery time of TcPO2 basal values after an induced ischemia of the limb is mandatory. The study also showed that there are no significant statistical correlations among the TcPO2 values, Doppler, and plethysmographic parameters.
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PMID:Transcutaneous oxygen tension behavior in the different stages of peripheral vascular disease and its correlation with ankle/arm pressure ratio and calf blood flow. 359 3

The distribution between carnitine and the acyl derivatives of carnitine reflects changes in the metabolic state of a variety of tissues. Patients with peripheral vascular disease (PVD) develop skeletal muscle ischemia with exertion. This impairment in oxidative metabolism during exercise may result in the generation of acylcarnitines. To test this hypothesis, 11 patients with PVD and 7 age-matched control subjects were evaluated with graded treadmill exercise. Subjects with PVD walked to maximal claudication pain at a peak O2 consumption (VO2) of 19.9 +/- 1.3 ml X kg-1 X min-1 (mean +/- SE). Control subjects were taken to a near-maximal work load at a VO2 of 31.3 +/- 1.0 ml X kg-1 X min-1. In patients with PVD, the plasma concentration of total acid-soluble, long-chain acylcarnitine and total carnitine was increased at peak exercise compared with resting values. Four minutes postexercise, the plasma short-chain acylcarnitine concentration was also increased. In control subjects taken to the higher work load, only the long-chain acylcarnitine concentration was increased at peak exercise. In patients with PVD, plasma short-chain acylcarnitine concentration at rest was negatively correlated with subsequent maximal walking time (r = -0.51, P less than 0.05). In conclusion, acylcarnitines increased in patients with PVD who walked to maximal claudication pain, whereas control subjects did not show equivalent changes even when taken to a higher work load. The relationship between short-chain acylcarnitine concentration at rest and subsequent exercise performance suggests that repeated episodes of ischemia may cause chronic accumulation of short-chain acylcarnitine in plasma in proportion to the severity of disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Carnitine metabolism during exercise in patients with peripheral vascular disease. 361 Sep 32

The recent recognition of the prevalence of asymptomatic ST-segment depression in patients with coronary artery disease demonstrates the poor sensitivity of using angina as a sign of myocardial ischemia. Possibly the greatest application of ambulatory ST-segment monitoring for the detection of asymptomatic ischemia is in diabetic patients. Coronary artery disease represents the ultimate cause of death in more than half of such patients and usually manifests itself prematurely at an advanced stage. The long-held clinical belief that infarction may be silent, or less painful, in patients with diabetes is supported by several retrospective studies (32 to 42 percent of diabetic patients lack angina at infarction, compared with only 6 to 15 percent of nondiabetic patients). Explanations for this observation have been remarkably deficient in the literature. One group has shown that in diabetic patients with painless infarction, the autonomic nerve fibers of the heart display typical lesions of autonomic neuropathy that may affect afferent sensory impulse transmission compared with those in several matched control groups. Except for a recent report from Italy, there are no data on the prevalence of asymptomatic ischemia in diabetic patients. There are obvious reasons to address this issue more comprehensively: first, given the high incidence of painless myocardial infarction, the frequency of asymptomatic ischemia may be very high; second, because the ability to evaluate patients with standard treadmill testing is limited in patients with peripheral vascular disease and diabetic neuropathy, ambulatory monitoring may be used on a more widespread basis; and third, given the higher than average incidences of sudden death and left ventricular dysfunction in diabetic patients compared with nondiabetic patients, ambulatory monitoring may represent a method of assessing the role of episodic ischemia in explaining these other cardiac events.
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PMID:Asymptomatic myocardial ischemia in diabetic patients. 370 56

Transcutaneous oxygen tension (TcPO2) is determined by blood flow and arterial oxygen tension (PaO2) and has been advocated as a measurement of tissue perfusion in peripheral vascular disease. The purpose of this study was to define the relationship between regional blood flow, PaO2, and TcPO2. TcPO2 sensors were placed on the skin of the anterior tibial regions of the hind limbs of 15 dogs. After occluding collateral blood flow, an external flow probe was placed around the femoral artery and an adjustable clamp was used to produce graded ischemia. Progressive reductions in blood flow were correlated with TcPO2 values at inspired oxygen concentrations (FiO2) of 0.21, 0.50, and 1.00. TcPO2 measured at room air decreased nonlinearly in relation to flow with a marked drop occurring below 20% of baseline flow. TcPO2 measured at increased FiO2 was dependent primarily on PaO2 at flow rates greater than 50% of baseline. With reduction in flow below 25% of baseline, TcPO2 was dependent solely on flow and was not augmented by increases in PaO2. The data suggest that TcPO2 can accurately reflect changes in blood flow to an extremity when flow is severely restricted.
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PMID:TcPO2 values in limb ischemia: effects of blood flow and arterial oxygen tension. 373 32

In 103 patients who underwent placement of 106 percutaneous wire-guided intraaortic balloon catheters between August 1983 and January 1986, all placements were successful and the average duration of counterpulsation was 3.4 +/- 1.6 days. During counterpulsation, 45 patients developed limb ischemia that required premature balloon removal in 29 patients. The development of limb ischemia was significantly related to the presence of diabetes (risk ratio 2.0), peripheral vascular disease (risk ratio 1.9), female gender (risk ratio 1.8) and the presence of a postinsertion ankle-brachial pressure index less than 0.8 (risk ratio 7.9). There was no association between the development of limb ischemia and age, body surface area, balloon size (10.5F/12F) or adequacy of anticoagulation. Fifteen patients underwent vascular surgery for treatment of balloon-related limb ischemia, which was associated with one operative death. Nine patients had persistent limb ischemia (seven asymptomatic, two symptomatic) at the time of hospital discharge. Improvements in wire-guided balloon technology have increased the probability of successful balloon placement over that of surgical placement and have reduced the incidence of major aortic injury, but there is no evidence that these improvements have reduced the incidence of limb ischemia or its sequelae. This should be borne in mind before proceeding with balloon insertion in patients with one or more risk factors for developing limb ischemia.
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PMID:Incidence and management of limb ischemia with percutaneous wire-guided intraaortic balloon catheters. 381 99

Peripheral vascular disease of the extremities causes ischemic pain and, at times, skin ulcerations and gangrene. It has been suggested that epidural spinal electrical stimulation (ESES) could improve peripheral circulation. Since 1978 we have used ESES in 34 patients with severe limb ischemia; all had resting pain and most had ischemic ulcers. Arterial surgery was technically impossible. Twenty-six patients had arteriosclerotic disease, one had Buerger's disease, and seven had severe vasospastic disorders. Ninety-four per cent of the patients experienced pain relief. ESES healed ulcers in 50% of those with preoperative nonhealing skin ulcerations. Seventy per cent of the patients showed improved skin temperature recordings. Only 38% of the stimulated arteriosclerotic patients underwent amputations during a mean followup period of 16 months, as compared to 90% of a comparable group of unstimulated patients. ESES is very promising in severe limb ischemia where reconstructive surgery is impossible or has failed.
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PMID:Epidural electrical stimulation in severe limb ischemia. Pain relief, increased blood flow, and a possible limb-saving effect. 387 10

This case report utilizes a recently popularized method of radiologic examination for peripheral vascular disease. In a diabetic foot with osteomyelitis, ischemia, and gangrene we have assessed patent arterial supply in the distal arterial tree. This examination has allowed the authors to accurately predict wound healing potential preoperatively at a specific anatomic level.
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PMID:Intravenous digital subtraction angiography and its use in amputation level consideration in the ischemic forefoot. 397 45

The accuracy of measurements of transcutaneous oxygen tension (Ptco2) in the diagnosis of peripheral vascular disease (PVD) may be significantly increased by stressing limb circulation with the use of temporary ischemia. The purpose of this study was to compare the transcutaneous oxygen recovery half-time (TORT) and the toe pulse reappearance time (PRT/2) in a series of patients with symptomatic PVD before and after vascular reconstruction. The TORT was defined as the time required to recover half of the decrease in the limb/chest Ptco2 ratio caused by temporary limb ischemia, and is conceptually comparable to the toe PRT/2, the time required to recover half of the control toe pulse amplitude. Measurement of TORT was found to be more feasible (100% vs 58%) and to have a greater diagnostic yield (100% vs 92%) than that of the toe PRT/2. When measured on the dorsum of the foot, TORT values were found to correlate well with the severity of symptoms of PVD; toe PRT/2 values did not correlate with severity of symptoms. Patients who underwent successful vascular reconstruction had significant improvement in their calf and foot TORT values after surgery (p less than .005 and .0005, respectively); postoperative values were similar to those obtained in normal subjects. Toe PRT/2 values usually improved postoperatively, but in many patients postoperative values overlapped with values that were considered abnormal. There was no overlap of TORT values in normal subjects with those in patients with symptomatic PVD. The measurement of TORT may be clinically useful for screening patients with suspected PVD and for assessing quantitatively the results of conservative and surgical therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transcutaneous oxygen recovery and toe pulse reappearance time in the assessment of peripheral vascular disease. 404 91

Two hundred seventy-five lower extremity amputations were performed over a 4-year interval for end-stage peripheral vascular disease. Fourteen patients (8.5%) of a total of 165 patients undergoing above-knee amputation (AKA) either suffered acute gangrenous ischemia of the AKA stump postoperatively, or were thought to be at high risk for same, and therefore underwent prophylactic inflow revascularization prior to or concomitant with AKA. The overall operative mortality rate was 28.5% in these 14 patients and was related either to inability to revascularize (two of three patients) or to the attempt to revascularize in the presence of a frankly necrotic amputation stump (three of five patients). Lower extremity amputation may be performed with an overall acceptably low mortality rate, which for our series is 0.9% for 113 below-knee amputation (BKA) and 2.8% for 140 AKA levels. Acute postoperative gangrene of the stump carries a high mortality rate and may be prevented by inflow revascularization prior to amputation. Three situations were identified as carrying a high risk for the subsequent development of gangrene: acute thrombosis of a prior combined inflow/outflow procedure, occlusion of the superficial femoral artery with an occluded/stenotic deep femoral artery and no palpable femoral pulse, and flat pulse volume recordings at the high thigh level. Patients who present for AKA with one of these indications should be considered as a candidate for prophylactic inflow revascularization prior to AKA to prevent ascending gangrene.
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PMID:Gangrene of the immediate postoperative above-knee amputation stump: role of emergency revascularization in preventing death. 405 46

The purpose of this study was to determine the effect of familial hyperlipoproteinemia (HLP) on peripheral vascular disease (PVD) and the extent to which the vascular disease (PVD) and the extent to which the vascular disease is modified by treatment of the lipoprotein disorder. PVD was detected plethysmographically by observing a diminished peak reactive hyperemia blood (PRHBF) following ischemia. The value for PRHBF in the extremity demonstrating the lowest response in 32 normal subjects (age 19-50 yr) was 39.6+/-1.5 SEM, ml/min per 100 g. Patients with untreated HLP. who had PRHBF below the lower limit of normal, were 2 of 11 type II, 9 of 12 type III, 1 of 10 type IV. As a group, patients with type III HLP showed diminished PRHBF (26.6 +/-3.0 ml/min per 100 g, P <0.01). In view of the high incidence of PVD and the striking reduction in serum lipids and complete resorption of xanthomas observed in type III HLP with therapy, six patients were studied before and after 3-6 months of treatment with a therapeutic diet and clofibrate. PRHBF in the most severely affected extremity increased markedly, from 20.4 +/-1.6 to 31.9 +/-1.8 ml/min per 100 g (P<0.01), indicating a dramatic increase in maximum blood flow to this extremity. In two type III patients with PVD not treated, no change in PRHBF occurred over 5 months. In two other type III patients the PRHBF increased 17% during the first 25 days of therapy concomitant with a 30% reduction in whole blood viscosity. Over the next 120 days, blood viscosity decreased only an additional 4.6% whereas the PRHBF increased 57%, indicating that the observed changes seen in the PRHBF with therapy of type III patients can be only minimally accounted for by changes in the viscosity of the blood. Thus, patients with type III HLP are particularly susceptible to the development of PVD and objective improvement of PVD can occur with medical treatment of this lipid transport disorder.
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PMID:Effects of hyperlipoproteinemias and their treatment on the peripheral circulation. 544 36


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