***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Four trials were included with a total of 220 participants (118 treated with atherectomy, 102 treated with balloon angioplasty) and 259 treated vessels (129 treated with atherectomy, 130 treated with balloon angioplasty). All studies compared atherectomy with angioplasty. No study was properly powered or assessors blinded to the procedures and there was a high risk of selection, attrition, detection and reporting biases. The estimated risk of success was similar between the treatment modalities although the confidence interval (CI) was compatible with small benefits of either treatment for the initial procedural success rate (Mantel-Haenszel risk ratio (RR) 0.92, 95% CI 0.44 to 1.91, P = 0.82), patency at six months (Mantel-Haenszel RR 0.92, 95% CI 0.51 to 1.66, P = 0.79) and patency at 12 months (Mantel-Haenszel RR 1.17, 95% CI 0.72 to 1.90, P = 0.53) following the procedure. The reduction in all-cause mortality with atherectomy was most likely due to an unexpectedly high mortality in the balloon angioplasty group in one of the two trials that reported mortality (Mantel-Haenszel RR 0.24, 95% CI 0.06 to 0.91, P = 0.04). Cardiovascular events were not reported in any study. There was a reduction in the rate of bailout stenting following atherectomy (Mantel-Haenszel RR 0.45, 95% CI 0.24 to 0.84, P = 0.01), and balloon inflation pressures were lower following atherectomy (mean difference -2.73 mmHg, 95% CI -3.48 to -1.98, P < 0.00001). Complications such as embolisation and vessel dissection were reported in two trials indicating more embolisations in the atherectomy group and more vessel dissections in the angioplasty group, but the data could not be pooled. From the limited data available, there was no clear evidence of different rates of adverse events between the atherectomy and balloon angioplasty groups for target vessel revascularisation and above-knee amputation. Quality of life and clinical and symptomatic outcomes such as walking distance or symptom relief were not reported in the studies. This review has identified poor quality evidence to support atherectomy as an alternative to balloon angioplasty in maintaining primary patency at any time interval. There was no evidence for superiority of atherectomy over angioplasty on any outcome, and distal embolisation was not reported in all trials of atherectomy. Properly powered trials are recommended.
Output:

In this review, we compared atherectomy to the more established treatments such as balloon angioplasty and bypass surgery. We identified four studies with a total of 220 participants. All studies compared atherectomy with balloon angioplasty. The studies were of low quality as there was no blinding of the procedures, the studies were not properly powered to show an effect, not all study outcomes were reported and a large number of the initial study populations did not complete the studies. Although the results of the meta-analyses were imprecise, the average effect of the two treatments was similar in terms of initial success and unobstructed arteries (patency) at six months or 12 months following the procedure. There was a lower risk of death with atherectomy, most likely due to an unexpectedly high number of deaths in the balloon angioplasty group in one of the two trials reporting deaths. Cardiovascular events were not reported in any of the included studies. There was a reduction in the rate of emergency stenting procedures following atherectomy, and balloon inflation pressures were lower following atherectomy. Complications such as formation of clots (embolisation) and tears along the vessels (vessel dissection) were reported in two trials indicating more embolisations in the atherectomy group and more vessel dissections in the angioplasty group but the data could not be combined. The limited data available indicated that there was no clear evidence of a difference between the atherectomy and balloon angioplasty groups for adverse events such as the need for re-intervention due to obstruction of the treated vessel and above-knee amputation. Quality of life and clinical and symptomatic outcomes such as walking distance or symptom relief were not reported in the studies. We showed that the limited evidence available does not support a significant advantage of atherectomy over conventional balloon angioplasty.