The use of secondary medical prevention after primary vascular reconstruction: studies on usage and effectiveness

Abstract

Peripheral arterial disease (PAD) is a common manifestation of symptomatic atherosclerosis that leads to a significantly elevated risk of cardiovascular events, including major limb loss, myocardial infarction, stroke and death. The prevalence proportions of PAD increase dramatically with age and appear to progress more aggressively in women than in men. Several studies have indicated that the use of secondary medical prevention is generally insufficient among PAD patients. However, current national and international guidelines recommend lipid-lowering and anti-platelet therapy, supplemented with aggressive blood pressure lowering treatment. We aimed to determine whether there were age-, gender-, geography or time related differences in the use of secondary medical prevention, following primary vascular reconstruction. We also sought to describe the prognoses for the same population, according to the association between the use of ACE/ATII inhibitors (angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists) or beta blockers and clinical outcomes (all cause mortality, myocardial infarction, stroke, major amputation and/or recurrent vascular surgery) in a population-based, long-term follow-up study. We established a data base by linking four population based administrative and health-care registries. All Danish patients undergoing primary vascular surgical reconstruction due to atherosclerotic disease between 1997 and 2007 were included and identified in the Danish Vascular Registry; a total of 20,761 patients were followed during a median of 582 days (range of 30 to 4,379 days). Data regarding all prescriptions filled by the study population were obtained from the Medical Registry of the Danish Medicines Agency. Study I: Age- and gender-related differences. We found moderate to low use of secondary medical prevention. However, this use has increased in recent years and the age- and gender-related differences in use have been reduced or eliminated. Study II: Geographic or time related differences. The use of evidence-based secondary medical prevention, especially lipid-lowering drugs, increased substantially over time, regardless of socio-demographic and clinical factors. No substantial differences in pharmacological use according to location of residence were observed. Study III: Use of ACE/ATII and prognosis. We found the use of ACE inhibitors to be associated with lower all cause mortality but also an increased long-term risk of recurrent vascular reconstruction and myocardial infarction. Study IV: Use of beta blockers and prognosis. We found beta blocker use to be associated with a lower risk of major amputation, but also an increased risk of new myocardial infarction and stroke. No association were found regarding all cause mortality or the risk of recurrent vascular surgery. In conclusion, the use of secondary medical prevention following primary vascular surgery (between 1996 and 2006 in Denmark) shifted towards a more evidence-based treatment, as reduction in age-, gender- and geography related differences were observed early in the study period. However, recommendations for the current clinical guidelines suggest that additional improvement can be made. The treatment of hypertension in PAD patients is complex, and our results are also complex but indicate that ACE/ATII and beta blockers are safe for use in symptomatic PAD patients.