David K. Beattie

Quality of life assessment in vascular disease: Towards a consensus

OBJECTIVES To review the assessment of quality of life in vascular disease, with particular reference to the Nottingham Health Profile and Medical Outcomes Study Short Form 36. DESIGN AND METHODS A detailed literature search of relevant publications. Trans-national and trans-cultural convergence and validity of these scales were assessed. RESULTS The Short Form 36 was found to be the most valid and reliable quality of life measure for use in an international vascular setting. CONCLUSION In the absence of a specific dedicated vascular disease quality of life measure, the Medical Outcomes Study Short Form 36 should be used as a quality of life measure in the assessment of vascular disease in an international setting.

Influence of patient-related variables on the outcome of carotid endarterectomy

PURPOSE Variability in outcome after carotid endarterectomy is well recognized. This study examines the importance of patient-related factors in determining outcome. METHODS Four hundred and sixty consecutive patients undergoing carotid endarterectomy for symptomatic severe (60% to 99%) internal carotid stenosis performed by one vascular surgeon have been studied prospectively. Patients were followed-up at 3, 6, 9, and 12 months and then yearly. Pre-, intra-, and perioperative details and follow-up information were entered on a database. RESULTS Multiple logistic regression identified a number of factors significantly associated with death and stroke. A history of crescendo transient ischemic attacks (TIAs) (p = 0.003, p = 0.0002) and being female (p = 0.03, p = 0.0001) were associated with both perioperative death and stroke within 30 days of operation, respectively. Deaths between 1 and 36 months were associated with ischemic heart disease (p = 0.03) and diabetes (p = 0.04), whereas stroke was associated with small internal carotid diameter (p = 0.02). The importance of symptoms at presentation on outcome was further emphasized by life-table analysis. In 98% of patients with amaurosis fugax, only 67% of those with crescendo TIAs were alive at 18 months (p < 0.01). The survival of patients with amaurosis was significantly better than those with TIAs (p < 0.01), transient stroke (p < 0.01), and progressive, stroke (p < 0.05). Similarly, postoperative stroke was significantly more common for patients with crescendo TIAs than those with amaurosis (p < 0.01), established stroke (p < 0.05), and TIA (p < 0.05). Transient stroke was associated with a poor outcome, with only 66% of patients being alive in 36 months and 14% having suffered a stroke (p < 0.05 compared with established stroke). CONCLUSION Presenting symptoms significantly predict outcome after carotid endarterectomy. This should be considered both in patient selection and comparison of patient series.

Have the results of infrainguinal bypass improved with the widespread utilisation of postoperative surveillance

OBJECTIVES The objectives of this study were to assess the impact of Duplex surveillance on the results of infrainguinal vein grafts. A review has been performed comparing the outcome of vein grafts undergoing Duplex surveillance plus prophylactic treatment of stenoses to that of vein grafts followed clinically. DESIGN, PATIENTS, AND METHODS Only studies providing information on occlusion rates were included. Mortality and limb salvage rates were also analysed but were not available from all studies. RESULTS 2680 surveillance and 3969 non-surveillance vein grafts were analysed. There was no significant difference between the two groups with respect to presence of critical ischaemia (p=0.3) and level of distal anastomosis (p>0.5). Surveillance identified 493 stenoses in 469 (19%) grafts, 397 (16%) grafts were treated by surgery (248; 62%) and angioplasty (149; 38%). Ninety-eight (26%) grafts developed recurrent stenoses. Total number of deaths, total number of occluded grafts and number of occlusions after 30 days were significantly greater for the non-surveillance group (p<0.001; p<0.001; p<0.01). Perioperative occlusion rates were not significantly different (p=0.1). Few surveillance studies reported limb salvage rates (6 of 17). The numbers of amputations were not significantly different between the two groups (p>0.5). CONCLUSIONS The patency of infrainguinal vein grafts would appear to be improved as a result of surveillance. However, no improvement in limb salvage has been demonstrated.

Clinical follow-up rather than duplex surveillance after carotid endarterectomy ☆ ☆☆

PURPOSE The value of duplex surveillance and the significance of contralateral carotid disease after endarterectomy have been assessed. METHODS Three hundred five patients were observed prospectively after carotid endarterectomy for a median time of 36 months (range, 6 to 96 months), with duplex surveillance performed at 1 day; 1 week; 3, 6, 9, and 12 months; and then each year after endarterectomy. RESULTS Thirty patients (10%) had ipsilateral symptoms (13 strokes, 17 transient ischemic attacks [TIAs]) at a median time of 6 months (range, 0 to 60 months). Life table analysis demonstrated that ipsilateral stroke was equally common for patients who had > or = 50% restenosis (3% at 36 months) and those who did not (6% at 36 months, p > 0.5). Twenty-three patients (8%) developed symptoms (stroke 5, TIA 14) attributable to the contralateral carotid artery at a median time of 9 months (range, 0 to 36 months) after endarterectomy. By life table analysis, 40% of patients with 70% to 99%, 6% with 50% to 69%, 1% with < 50% contralateral internal carotid stenosis, and 5% with contralateral carotid occlusion at the time of endarterectomy had a contralateral TIA in the 36 months after endarterectomy (p < 0.01). However, contralateral stroke was not significantly more common for patients with severe contralateral internal carotid stenosis demonstrated at the time of endarterectomy (< 50% stenosis, 0%; 50% to 69%, 3%; 70% to 99%, 7%; occlusion, 6% stroke rate at 36 months). Seven of the 32 patients who developed progression of contralateral disease had a TIA, compared with 11 of 227 patients who did not develop progression of contralateral disease (p < 0.01). None of the 12 patients who progressed from a < 70% to a 70% to 99% contralateral stenosis had a stroke. CONCLUSIONS After carotid endarterectomy restenosis is rarely associated with symptoms; contralateral stroke is rare and is not associated with progressive internal carotid artery disease suitable for endarterectomy. This study has shown no benefit from long-term duplex surveillance after carotid endarterectomy. Selective clinical follow-up of patients who have high-grade contralateral stenoses would appear more appropriate.

Circumferential stretching of saphenous vein smooth muscle enhances vasoconstrictor responses by Rho kinase-dependent pathways

OBJECTIVE Surgical preparation and/or pulsatile arterial perfusion of saphenous vein increases the sensitivity of vein rings to calcium mobilising agonists such as phenylephrine. We have investigated the mechanism(s) underlying this effect. METHODS We have used an ex vivo flow circuit, with simulated arterial or venous flows (mean pressure 100 and 20 mmHg, respectively), to investigate the sensitivity of human saphenous vein to phenylephrine, 5-hydroxytryptamine (5-HT) and KCl, using organ chamber pharmacology. RESULTS After 90 min of pulsatile arterial perfusion the mean maximum tension induced by KCl had increased from 4.7 to 11.1 g (n=5), by phenylephrine had increased from 4.4 to 10.2 g (n=8) and by 5-HT had increased from 4.4 to 6.7 g (n=10), all P<0.01. Phenylephrine did not augment the tension in vein rings maximally precontracted with KCl (n=4). The EC(50) for KCl was unchanged after pulsatile arterial perfusion (n=5), but for phenylephrine and 5-HT there were significant reductions from 14+/-5 to 2+/-1 microM (n=8) and from 1.0+/-0.4 to 0.20+/-0.06 microM (n=10), respectively. The rate of contraction (in response to 3 microM phenylephrine) increased from 0.11 g/min to 0.37 g/min, P<0.02, after arterial perfusion (n=4). These changes in contractile properties (to phenylephrine) were endothelium-independent, evident within 5 min of simulated arterial perfusion. The changes in contractile properties could be abrogated by external stenting of the vein (to attenuate circumferential deformation) or inclusion in the perfusate of a vasodilator, e.g., cromakalim (5 microM) or the selective Rho kinase inhibitor Y-27632 (20 microM). The heightened sensitivity and contractility to phenylephrine was maintained after inclusion of adenosine (100 microM), gadolinium (10 microM) or cycloheximide (10 microM) in the vein perfusate. CONCLUSIONS The circumferential deformations imposed by simulated arterial perfusion alter the vasomotor responses of saphenous vein smooth muscle. These effects are independent of new protein synthesis or the activation of stretch activated cation channels. The Rho kinase pathway appears to mediate the signalling mechanisms leading to increased agonist-induced tension and the increased sensitivity to vasoconstrictors.

THE EFFECTS OF POTASSIUM CHANNEL OPENERS ON SAPHENOUS VEIN EXPOSED TO ARTERIAL FLOW

OBJECTIVES To assess the sensitivity of saphenous vein to potassium channel opening drugs (KCOs). METHODS Saphenous vein, harvested at bypass surgery or high ligation for correction of varicose veins, was exposed to an in vitro flow circuit and vasomotor responses assessed by organ bath pharmacology. OUTCOME MEASURES Effective drug concentrations for 50% reduction in vein ring tension (IC50). RESULTS Vein rings pre-contracted with phenylephrine showed a concentration-dependent relaxation to all the KCOs tested with a potency ranking of HOE 234 > cromakalim > pinacidil > diazoxide. The relaxation to cromakalim was endothelium-independent and was inhibited by glibenclamide (an ATP-sensitive K+ channel blocker). The sensitivity of vein rings to cromakalim increased after exposure to arterial flow conditions for 90 minutes (IC50 before 1.7 +/- 0.25 microM and after 0.25 +/- 0.08 microM, p > 0.001). This effect was not evident after 90 min of venous flow conditions, 2.19 +/- 0.49 microM. When the workload on vein, exposed to arterial flow conditions, was reduced mechanically by external stenting with PTFE the increased sensitivity to cromakalim was abolished. CONCLUSIONS Saphenous vein has ATP-sensitive K+ channels responsive to KCOs. The increased sensitivity to cromakalim, induced by arterial flow conditions, may represent an endogenous protective mechanism limiting ischaemic damage resulting from the higher workload imposed on grafted vein.