Background and purpose: Restenosis after percutaneous transluminal angioplasty is a prevalent phenomenon that might lead to repetition of angioplasty, open heart surgery, myocardial infarction, and death. This study, drawing on extended Cox regression model, pursues examining effective factors on the time to incidence of restenosis.
Materials and methods: In this historical cohort study, 421 patients attending Ayatollah Moosavi Hospital, Zanjan, Iran (from April 2009 to June 2011) for drug-eluting stent implementation were followed up until June 2015 for time of incidence of restenosis. In next stage, some demographic variables and clinical records were studied. The proportional hazards assumption did not hold, so, to model this survival data, extended Cox regression was applied.
Results: Compared to other patients, the hazard ratio of restenosis in patients with drug abuse and hyperlipidemia was 2.09 times and 1.91 times more, respectively. Also, two years after angioplasty, the hazard ratio of restenosis in patients over 60 years old 2 times, diabetic patients 2.91 times, and in patients suffering from hypertension was 2.49 times more than those of other patients (P<0.05).
Conclusion: In this study, drug abuse and a history of hyperlipidemia constitute effective factors on the incidence of restenosis. Compared to these, being over 60 years of age and suffering from diabetes and hypertension had lower effects. Accordingly, preventing the risk factors mentioned and periodic follow-ups are highly suggested in patients with such conditions.