Sammendrag
Medical imaging has rapidly increased in numbers and cost. Evaluation of diagnostic methods has much focused on accuracy, but less on cost and hazard. Advanced tests for coronary artery disease are expensive and carry a risk. In heart transplant (HTx) patients, coronary vasculopathy is prevalent, and annual follow-up comprises a coronary angiography. Less costly and low-risk techniques with adequate accuracy are desired. In this study we tested the diagnostic accuracy and cost of three available medical techniques to detect coronary artery stenosis (CAD) in HTx patients. Methods: Fifty stable HTx patients aged (mean±SD) 57±8 years were studied during annual routine control with dobutamine stress echocardiography (dobECHO), dobutamine 99mTc-tetrofosmin emission tomography (dobSPET) and exercise ECG (exECG), and compared with coronary angiography. Cost of methods were derived from hospital accountancy data. Results: Significant coronary artery stenosis in ≥1 major epicardial vessel was present in 14 patients (28.0%), but only 16 (32.0%) had complete normal angiograms. Sensitivity, specificity, and accuracy for CAD as compared to angiograms, was for dobECHO: 67%, 91%, and 82%; for dobSPET: 71%, 74%, and 73%; and for exECG: 20%, 91%, and 70%, respectively. By combining dobECHO with echocardiographic wall motion analysis, the rate of false negatives was reduced to 4%. Cost of dobECHO, dobSPET and exECG was estimated to 0.58, 1.45, and 0.25 times cost of angiography. DobSPET gives similar radiation exposure (7 mSv) as angiography. Conclusion: DobECHO and dobSPET are feasible tests in HTx patients. DobECHO or dobSPET alone or combined with echocardiographic resting wall motion analysis, can be used with acceptable accuracy for identifying HTx patients in whom routine coronary angiography intermittently can be deferred. Of these, dobECHO is the least expensive, and carries the least risk to the patient. ExECG has low accuracy and cannot be recommended in HTx in spite of low cost.