Tuesday, September 11, 2007

Swiss Interventional Study on Silent Ischaemia type I

Effects of anti-ischaemic drug therapy in silent myocardial ischaemia type I: the Swiss Interventional Study on Silent Ischaemia type I (SWISSI I): a randomized, controlled pilot study

Paul Erne1, Andreas W. Schoenenberger2, Michel Zuber1, Dieter Burckhardt3, Wolfgang Kiowski4, Paul Dubach5, Therese Resink3 and Matthias Pfisterer3,*

Aims: To determine the effect of anti-ischaemic drug therapy on long-term outcomes of asymptomatic patients without coronary artery disease (CAD) history but silent exercise ST-depression.

Methods and results: In a randomized multicentre trial, 263 of 522 asymptomatic subjects without CAD but at least one CAD risk factor in whom silent ischaemia by exercise ECG was confirmed by stress imaging were asked to participate. The 54 (21%) consenting patients were randomized to anti-anginal drug therapy in addition to risk factor control (MED, n = 26) or risk factor control-only (RFC, n = 28). They were followed yearly for 11.2 ± 2.2 years. During 483 patient-years, cardiac death, non-fatal myocardial infarction, or acute coronary syndrome requiring hospitalization or revascularization occurred in 3 (12%) of MED vs. 17 (61%) of RFC patients (P < 0.001). In addition, MED patients had consistently lower rates of exercise-induced ischaemia during follow-up, and left ventricular ejection fraction remained unchanged (–0.7%, P = 0.597) in contrast to RFC patients in whom it decreased over time (–6.0%, P = 0.006).

Conclusion: Anti-ischaemic drug therapy and aspirin seem to reduce cardiac events in subjects with asymptomatic ischaemia type I. In such patients, exercise-induced ST-segment depression should be verified by stress imaging; if silent ischaemia is documented, anti-ischaemic drug therapy and aspirin should be considered

Eur Heart J 2007; 28: 2110-2117


Cohn Type I refers to asymptomatic individuals without known coronary artery disease (CAD) and Cohn Types II and III to patients with known CAD. Those with prior myocardial infarctions (MIs) who are asymptomatic are Type II, and those with CAD and both silent and symptomatic ischaemic episodes are Type III.1 In the last decade a dedicated group of Swiss cardiologists led by Dr Mathias Pfister of the Basel University Hospital have conducted a long-term series of clinical studies involving patients with Types I and II silent ischaemia. By providing a ‘new look’ at the syndrome of silent ischaemia they have contributed important clinical data to aid in its management. They have now described the results of anti-ischaemia drug therapy in Type I patients (studied in their SWISS I trial);2 their SWISS II data dealing with Type 2 patients and also recently published3 will be commented on later in this editorial.

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