Outcome after Catheter-Directed Thrombolysis of Occluded Prosthetic Femoropopliteal Bypasses: A prospective study

Purpose: To evaluate the outcome after catheter-directed thrombolysis of occluded femoropopliteal prosthetic bypasses with the distal anastomosis above the knee.

Material and Methods: Twenty-one patients were included in this prospective study. End-hole catheters, a bolus dose and continuous infusion of recombinant tissue-plasminogen activator (rt-PA) were used, with a median total dose of 10 mg (range 7–20 mg).

Results: With an intra-thrombotic position of the catheter, total or subtotal lysis was obtained in 19 of 21 patients (90%). No serious complications occurred. In 9 patients, the stenoses were successfully treated with balloon angioplasty (PTA, n = 5), local thrombectomy/extension of bypass (n = 3), or with a new bypass (n = 1). After a median observation time of 18 months (6–24), 5 patients had open bypass. Re-occlusion occurred in all (6/6) bypasses in which no flow-limiting lesion was discovered, in all (4/4) bypasses treated twice with thrombolysis, as well as in all bypasses in which stenoses had not been adequately treated (3/3). One bypass re-occluded immediately due to poor runoff.

Conclusion: In the present study, 19/21 infra-inguinal prosthetic bypasses were successfully treated with catheter-directed thrombolysis. However, re-occlusion often took place, especially in bypasses without flow-limiting lesions. If re-occlusion occurs in a bypass in which no stenoses were revealed during the primary thrombolysis procedure, a second catheter-directed thrombolytic treatment does not seem to be warranted. Our results confirm that treatment of flow-limiting lesions is a prerequisite for maintaining patency.

Catheter-directed thrombolysis vs. anticoagulant therapy alone in deep vein thrombosis: results of an open randomized, controlled trial reporting on short-term patency

BACKGROUND

Approximately one in four patients with acute proximal deep vein thrombosis (DVT) given anticoagulation and compression therapy develop post-thrombotic syndrome (PTS). Accelerated removal of thrombus by thrombolytic agents may increase patency and prevent PTS.

OBJECTIVES

To assess short-term efficacy of additional catheter-directed thrombolysis (CDT) compared with standard treatment alone.

PATIENTS AND METHODS

Open, multicenter, randomized, controlled trial. Patients (18-75 years) with iliofemoral DVT and symptoms < 21 days were randomized to receive additional CDT or standard treatment alone. After 6 months, iliofemoral patency was investigated using duplex ultrasound and air-plethysmography assessed by an investigator blinded to previous treatment.

RESULTS

One hundred and three patients (64 men, mean age 52 years) were allocated additional CDT (n = 50) or standard treatment alone (n = 53). After CDT, grade III (complete) lysis was achieved in 24 and grade II (50%-90%) lysis in 20 patients. One patient suffered major bleeding and two had clinically relevant bleeding related to the CDT procedure. After 6 months, iliofemoral patency was found in 32 (64.0%) in the CDT group vs. 19 (35.8%) controls, corresponding to an absolute risk reduction (RR) of 28.2% (95% CI: 9.7%-46.7%; P = 0.004). Venous obstruction was found in 10 (20.0%) in the CDT group vs. 26 (49.1%) controls; absolute RR 29.1% (95% CI: 20.0%-38.0%; P = 0.004). Femoral venous insufficiency did not differ between the two groups.

CONCLUSIONS

After 6 months, additional CDT increased iliofemoral patency from 36% to 64%. The ongoing long-term follow-up of this study will document whether patency is related to improved functional outcome.

External Venous Valve Plasty (EVVP) in Patients with Primary Chronic Venous Insufficiency (PCVI)

OBJECTIVES

To evaluate the patency of EVVP and its effect in symptom relief, ulcer healing and ulcer-free period in patients with PCVI.

METHODS

Between 1993 and 2004, 1800 patients with CVI were evaluated and seventeen with PCVI were selected for EVVP. They were all investigated with ambulatory venous pressure measurement (AVP), colour duplex ultrasound (CDU), ascending venography and descending video venography. The CEAP classification was used to group the patients. Six patients were C4, four C5 and seven C6. All had deep reflux and high levels of AVP.

RESULTS

All procedures were technically successful. The ulcer healing rate was 4/7 (57%) within 3 months. All C4 patients experienced symptom improvement postoperatively and had a median recurrence free period of 72 (range 60-122) months. The C5 group had an median ulcer free period of 61 months (12-72) and the C6 of median 48 (12-72) months. Single valve plasties (4) reached a median competence period of 48 months (12-72), 12 multiple valve plasties at the same level show a median 78 months (63-122) and 10 multilevel repairs median 54 months (12-96). Multiple valve plasties at the same level (multi-station plasties) performed on the C4 group seemed to yield the longest durability with a median of 103 months (84-122).

CONCLUSION

EVVP with an ulcer healing rate of 57% and satisfactory symptom improvement seems to be an alternative of surgical treatment for selected patients with PCVI. The durability of this technique seems to be related to clinical severity and the multiplicity of repairs.

Gadolinium-enhanced Magnetic Resonance Angiography, Colour Duplex and Digital Subtraction Angiography of the Lower Limb Arteries from the Aorta to the Tibio-peroneal Trunk in Patients with Intermittent Claudication

OBJECTIVES

To evaluate the sensitivity, specificity, positive and negative predictive value of contrast-enhanced (gadolinium) magnetic resonance imaging (CE-MRA) and colour duplex ultrasound (CDU) of lower limb arteries.

DESIGN

Prospective, single centre study.

MATERIAL AND METHODS

A consecutive series of 58 patients with intermittent claudication (IC) were examined with CE-MRA and CDU from the infrarenal aorta to the tibio-peroneal trunk with digital subtraction angiography (DSA) as reference. The arterial tree was divided into 15 segments, pooled into three regions; suprainguinal, thigh and knee. Sensitivity, specificity, positive and negative predictive values for significant obstructions were calculated. Cohen Kappa statistics was used to establish agreement between the three methods.

RESULTS

The sensitivity (specificity in parentheses) for significant obstructions in the suprainguinal region were 96% (94%) for CE-MRA and 91% (96%) for CDU, in the thigh region 92% (95%) for CE-MRA and 76% (99%) for CDU, and in the knee region 93% (96%) for CE-MRA and 33% (98%) for CDU. CDU failed to visualize 10% of suprainguinal, 2% of thigh and 13% of knee-region arterial segments.

CONCLUSIONS

Both CE-MRA and CDU are good alternatives to DSA in the suprainguinal- and thigh-region. In the knee region only CE-MRA can be relied upon as an alternative to DSA. Imaging by CDU is not suited to situations were evaluation of runoff vessels is important.

Effects of mechanical irritation on the autonomic part of the median nerve

The diagnosis of median nerve compression is generally based upon a prolonged nerve conduction velocity although this frequently is preceded by clinical symptoms for years. The present study was designed to identify indicators for early decompression of the median nerve in patients exhibiting symptoms compatible with carpal tunnel syndrome (CTS). Microvascular perfusion in finger tip skin and skin temperature were studied during dorsiflexion of the hand prior to and following a manual exercise test in control subjects and in patients with clinical symptoms and signs of CTS. Evaluation of the microcirculation was performed using photoplethysmography (PPG) and laser Doppler fluxmetry (LDF). Fingertip skin temperature was measured by thermography and was significantly reduced in patients after exercise (P < 0.001), whereas no significant change occurred in control subjects. During increasing degrees of dorsiflexion (0-75 degrees ) and after manual exercise, fingertip skin perfusion remained unchanged in both patients and control subjects. In conclusion, patients with low-grade CTS experience skin temperature reduction, presumably caused by increased sweating as opposed to a generally suspected vasoconstriction. These autonomic median nerve dysfunctions provide the physiological basis for the use of thermography in confirming low-grade CTS.

Subintimal Angioplasty in the Treatment of Patients with Intermittent Claudication: Long Term Results

OBJECTIVES

Reporting the long-term results of subintimal angioplasty (SA) in patients with intermittent claudication (IC).

DESIGN

A prospective study.

PATIENTS

One hundred and sixteen SA procedures were performed in 104 patients, from February 1997 to January 2000.

METHODS

This is a prospective study of patients treated for IC with infrainguinal SA. Primary assisted patency rates were calculated, also on intention to treat basis. Univariate and multivariate Cox regression tests were used to assess whether patency was correlated with co-morbidities, run-off or occlusion length.

RESULTS

There was no early mortality. Technical success was achieved in 101 cases (87%). Primary assisted patency rates on intention to treat basis (116 cases) at 6, 12, 36 and 60 months were 69, 62, 57 and 54%, respectively. For successfully recanalized patients (101 cases) these respective numbers are 79, 70, 66 and 64%. Length of occlusion, age and male gender were independent risk factors for reocclusion.

CONCLUSIONS

The satisfactory results obtained in the present study are probably due to two main factors. First, the three participating radiologist are highly skilled and experienced. Secondly, a conscientious surveillance was adhered to, so that restenoses could be diagnosed and treated early. SA is a relevant alternative to bypass surgery in patients with disabling IC due to long femoro-popliteal occlusions. It is far less traumatic than conventional vascular reconstructions, complications are few and not serious. Very importantly, SA never interfered with later successful vascular surgery. Therefore, we have adopted SA as the primary treatment for patients with IC when medical treatment alone has not been satisfactory.

Outcome after catheter-directed thrombolysis of occluded prosthetic femoropopliteal bypasses. A prospective study

PURPOSE

To evaluate the outcome after catheter-directed thrombolysis of occluded femoropopliteal prosthetic bypasses with the distal anastomosis above the knee.

MATERIAL AND METHODS

Twenty-one patients were included in this prospective study. End-hole catheters, a bolus dose and continuous infusion of recombinant tissue-plasminogen activator (rt-PA) were used, with a median total dose of 10 mg (range 7-20 mg).

RESULTS

With an intra-thrombotic position of the catheter, total or subtotal lysis was obtained in 19 of 21 patients (90%). No serious complications occurred. In 9 patients, the stenoses were successfully treated with balloon angioplasty (PTA, n=5), local thrombectomy/extension of bypass (n=3), or with a new bypass (n=1). After a median observation time of 18 months (6-24), 5 patients had open bypass. Re-occlusion occurred in all (6/6) bypasses in which no flow-limiting lesion was discovered, in all (4/4) bypasses treated twice with thrombolysis, as well as in all bypasses in which stenoses had not been adequately treated (3/3). One bypass re-occluded immediately due to poor runoff.

CONCLUSION

In the present study, 19/21 infra-inguinal prosthetic bypasses were successfully treated with catheter-directed thrombolysis. However, re-occlusion often took place, especially in bypasses without flow-limiting lesions. If re-occlusion occurs in a bypass in which no stenoses were revealed during the primary thrombolysis procedure, a second catheter-directed thrombolytic treatment does not seem to be warranted. Our results confirm that treatment of flow-limiting lesions is a prerequisite for maintaining patency.

Lipoprotein(a), other lipoproteins and hemostatic profiles in patients with ischemic stroke: the relation to cardiogenic embolism

Lipoprotein and hemostatic profiles including coagulation inhibitors were determined in 136 patients with acute ischemic stroke. Based on clinical examination, cerebral computed tomography, Doppler ultrasonography of precerebral arteries and transthoracic echocardiography, the strokes were classified as cardioembolic (n = 38), non-cardioembolic (n = 92), and mixed cardioembolic/hypertensive (n = 6). Patients with cardioembolic stroke were older than patients with non-cardioembolic stroke. Lipoprotein(a) was higher in the cardioembolic than in the non-cardioembolic group. Lipoprotein(a) was not significantly correlated to the other lipid levels and may represent an independent lipid risk factor. The non-cardioembolic group had higher levels of total cholesterol, triglycerides, total cholesterol/high-density lipoprotein cholesterol ratio, low-density lipoprotein cholesterol, apolipoprotein A1, and apolipoprotein B. The cardioembolic group had higher concentrations of fibrinogen and D-dimer, and lower levels of antithrombin, protein C, protein S and heparin cofactor 2 than the non-cardioembolic group. The differences in the hemostatic profile are consistent with thrombosis due to activated coagulation being more involved in the pathogenesis of cardioembolic than of non-cardioembolic stroke. Lipoprotein(a) seems to be more associated with coagulation markers of thrombosis than with atherosclerosis, whereas the other lipids mainly seem to be risk factors for atherosclerosis.

Oedema in the lower limb of patients with chronic critical limb ischaemia (CLI)

OBJECTIVE

approximately 70% of patients with chronic critical limb ischaemia (CLI) show clinical signs of oedema in the distal leg and foot. The primary aim of the present investigation was to quantify this oedema. In addition we investigated whether oedema formation could be due to deep venous thrombosis (DVT).

METHODS

fifteen patients with unilateral CLI and oedema were studied, four males and 11 females, with a mean age of 77+/-10.3 years. Water displacement volumetry (WDV) was used to measure limb volume. Colour duplex ultrasound (CDU) and venous occlusion plethysmography (VOP) were applied to exclude functionally significant DVT. Blood chemistry was analysed to screen for some causative factors of generalised oedema formation.

RESULTS

the mean volume of the limbs with CLI was 9% greater than the contralateral limbs (1279+/-325 ml vs. 1179+/-298 ml). None of the patients had functionally significant DVT. The mean plasma albumin concentration was reduced at 28.5+/-6.6 g/l.

CONCLUSION

a significantly reduced plasma albumin concentration cannot be regarded as a causative factor, since the oedema is unilateral. The aetiology of oedema formation is probably multifactorial, and further investigations are under progress to elucidate relevant pathogenetic factors.

The role of blood perfusion and tissue oxygenation in the postischemic transcutaneous pO2 response

The transcutaneous pO2 (TCpO2) response following release of tourniquet cuff occlusion is expressed as oxygen reappearance time (ORT) and oxygen recovery index (ORI). In the present study the effects of blood perfusion and tissue oxygenation on ORT and ORI in healthy control subjects and two patient groups with peripheral arterial insufficiency were assessed. In control subjects, ORT reflects diffusion time for O2 molecules from capillaries to the TCpO2 sensor. In patients with claudication, ORT was prolonged probably because of delayed postischemic reperfusion and reduced tissue oxygenation. In patients with critical ischemia, prolonged ORT seems to be attributed more to reduced tissue oxygenation than to delayed postischemic reperfusion. ORI in control subjects and patients with claudication apparently depends more on capillary pO2 than on magnitude and duration of the postischemic reperfusion. In patients with critical ischemia, ORI is more related to decreased O2 delivery subsequent to reduced or absent reactive hyperemia response. In addition, increased O2 extraction ("O2 steal") and extensive countercurrent O2 exchange during low flow states may reduce ORT and ORI in severely ischemic skin.

The relation between changes in capillary morphology induced by ischemia and the postischemic transcutaneous pO2 response

The postischemic transcutaneous pO2 response following release of tourniquet cuff occlusion is expressed as oxygen reappearance time (ORT) and oxygen recovery index (ORI). ORT and ORI have been assessed in patients with peripheral arterial insufficiency. The purpose of the present investigation was to study the relationship between capillary structure of the skin and ORT and ORI in patients with critical ischemia. ORT and ORI were measured when breathing ambient air and supplemental oxygen. The capillary morphology was studied and classified according to severity (capillary stage A, B or C) in the same ischemic area of the skin using vital capillary microscopy (VCM). ORT and ORI were assessed against the capillary morphology stages. Based on both VCM and transcutaneous pO2 (TCpO2) findings, patients could be separated into two groups. Group I had normal or minor changes of capillary morphology and significantly better ORT and ORI values than group II. Group II had poor ORT and ORI values, impaired response to breathing of supplemental oxygen and pathological capillary morphology. The results from this study indicate that major changes in capillary structure observed in critical ischemic skin may hamper O2 diffusion and modify both ORT and ORI. The influence of structural capillary changes on the TCpO2 parameters probably increases with the extent of morphological deterioration.

Pre- and postischemic transcutaneous oxygen tension measurements and the determination of amputation level in ischemic limbs

The value of transcutaneous pO2 (TCpO2) measurements in determining amputation levels was studied in patients with atherosclerotic lower limb ischemia. A postischemic TCpO2 response did not predict healing of the amputation stump better than measurements at rest. No minimal resting or postischemic TCpO2 was found below which healing could not occur. However high TCpO2 values probably are indicative of a good healing potential. In patients with poor skin viability, assessed clinically, the method may be of value; in some cases TCpO2 values compatible with healing may be found. Attention should be paid to the TCpO2 sensor as its characteristics may influence the measurements in patients with critical ischemia causing underestimation of tissue pO2.

Laser Doppler flowmetry in evaluation of lower limb resting skin circulation. A study in healthy controls and atherosclerotic patients

Laser Doppler flowmetry (LDF) was used to evaluate lower limb resting skin perfusion in sixty subjects divided into four groups: healthy young and elderly controls, and patients with intermittent claudication or critical ischaemia. Measurements were performed in pulp skin containing microvascular AV anastomoses and in the skin of leg and thigh where these shunts are absent. In toe pulp controls and claudicators had higher perfusion values than in leg and thigh skin (p less than 0.01), indicating that the LDF method evaluates flow both in nutritional capillaries, AV anastomoses and in dermal vascular plexa. Elderly controls had higher flux values in the pulp than claudicators (p less than 0.01), and claudicators had higher values than patients with critical ischaemia (p less than 0.01), showing that LDF could differentiate between the clinical groups. Study of reproducibility confirmed that values were reproducible on a given population. Day to day variation was considerable in individual subjects, probably because of changes in sympathetic vascular tone and because of different vascular architecture in the measuring volumes which are only some few mm3. The fact that LDF measures total skin blood flow explains why several papers have found a poor correlation between LDF and methods which mainly evaluate nutritional blood flow. The method is non-invasive, continuous and easy to perform. Laser Doppler flowmetry may have several clinical applications, like evaluating progress of atherosclerotic disease or therapeutic effects of drugs or operations. To increase the reproducibility of resting skin flux measurements local heating of the skin is recommended and the measurements should be performed with an integrating probe, which averages the readings obtained at several positions simultaneously.

Laser Doppler flux reappearance time (FRT) in patients with lower limb atherosclerosis and healthy controls

Laser doppler flowmetry was used to examine the skin circulation in the lower limb during postischaemic reactive hyperaemia. Flux reappearance time (FRT), the time from tourniquet deflation to the start of the hyperaemic response, was determined from the recorded curves, and the aim of the study was to investigate whether FRT is dependent on total limb vascular resistance or to the resistance in a segment of the limb. FRT was first compared with the clinical situation of the examined subjects, and with the resting ankle blood pressure index (API). Controls had an immediate hyperaemic response (FRT less than or equal to 3 s), while patients with critical ischaemia had prolonged FRT (greater than 48 s). Among the claudicators there was no significant correlation between API or ankle blood pressure and FRT. When FRT was compared with angiography, all claudicators who only had significant atherosclerosis proximal to the tourniquet, had FRT values within the control range. Patients who only had distal atherosclerosis had prolonged values (greater than 15 s), indicating that FRT is independent of proximal atherosclerosis and reflects the vascular resistance in the arteries in the segment between the tourniquet and the measuring probe. This interpretation was supported by the reduction of pathologically prolonged FRT when the distance between the tourniquet and the measuring site was reduced. We conclude that FRT as measured by this technique seems to reflect the vascular resistance in the run off arteries distal to the tourniquet.