Nationwide Experience of Cardio- and Cerebrovascular Complications During Infrainguinal Endovascular Intervention for Peripheral Arterial Disease and Acute Limb Ischaemia

Assessment of Minimum Important Difference and Substantial Clinical Benefit with the Vascular Quality of Life Questionnaire-6 when Evaluating Revascularisation Procedures in Peripheral Arterial Disease

OBJECTIVES

Patient reported outcomes are increasingly used to assess outcomes after peripheral arterial disease (PAD) interventions. VascuQoL-6 (VQ-6) is a PAD specific health-related quality of life (HRQoL) instrument for routine clinical practice and clinical research. This study assessed the minimum important difference for the VQ-6 and determined thresholds for the minimum important difference and substantial clinical benefit following PAD revascularisation.

MATERIALS AND METHODS

This was a population-based observational cohort study. VQ-6 data from the Swedvasc Registry (January 2014 to September 2016) was analysed for revascularised PAD patients. The minimum important difference was determined using a combination of a distribution based and an anchor-based method, while receiver operating characteristic curve analysis (ROC) was used to determine optimal thresholds for a substantial clinical benefit following revascularisation.

RESULTS

A total of 3194 revascularised PAD patients with complete VQ-6 baseline recordings (intermittent claudication (IC) n = 1622 and critical limb ischaemia (CLI) n = 1572) were studied, of which 2996 had complete VQ-6 recordings 30 days and 1092 a year after the vascular intervention. The minimum important difference 1 year after revascularisation for IC patients ranged from 1.7 to 2.2 scale steps, depending on the method of analysis. Among CLI patients, the minimum important difference after 1 year was 1.9 scale steps. ROC analyses demonstrated that the VQ-6 discriminative properties for a substantial clinical benefit was excellent for IC patients (area under curve (AUC) 0.87, sensitivity 0.81, specificity 0.76) and acceptable in CLI (AUC 0.736, sensitivity 0.63, specificity 0.72). An optimal VQ-6 threshold for a substantial clinical benefit was determined at 3.5 scale steps among IC patients and 4.5 in CLI patients.

CONCLUSIONS

The suggested thresholds for minimum important difference and substantial clinical benefit could be used when evaluating VQ-6 outcomes following different interventions in PAD and in the design of clinical trials.

Two-year results from a randomized clinical trial of revascularization in patients with intermittent claudication

Background

Intermittent claudication is associated with significant impairment of health-related quality of life. The use of revascularization techniques to improve health-related quality of life remains controversial.

Methods

Patients with intermittent claudication due to iliac or femoropopliteal peripheral artery disease were enrolled in the IRONIC trial. They were randomized to either best medical therapy (BMT), including a structured, non-supervised exercise programme, or revascularization with either endovascular or open techniques in addition to BMT. The primary outcome was health-related quality of life at 2 years assessed using the Short Form 36 (SF-36®) questionnaire. Secondary outcomes included VascuQoL questionnaire results, treadmill walking distances and achievement of patient-specified treatment goals.

Results

Both randomized groups had improved health-related quality of life and treadmill walking distance at 2-year follow-up. Overall SF-36® physical component summary score, three SF-36® physical domain scores, overall VascuQoL score, and three of five VascuQoL domain scores showed significantly greater improvement in the group that also received invasive treatment. Intermittent claudication distance on a graded treadmill improved more in the revascularization + BMT group (117 versus 55 m; P = 0·003) whereas maximum walking distance and 6-min walk test distance were similar. Some 44 per cent of patients in the revascularization + BMT group reported they had fully achieved their treatment goal versus 10 per cent in the BMT group.

Conclusion

A revascularization strategy with unsupervised exercise improved health-related quality of life and intermittent claudication distance more than standard BMT and an unsupervised exercise programme in patients with lifestyle-limiting claudication. Registration number: NCT01219842 (http://www.clinicaltrials.gov).