Usefulness of exercise tomographic myocardial perfusion imaging for detection of restenosis after coronary stent implantation

Autor: Salvatore Musumeci, Giuseppe Coco, Rosario Foti, Giuseppe Giuffrida, Corrado Tamburino, Giovanni Russo, Salvatore Azzarelli, Alfredo R. Galassi, Giovanni Condorelli
Rok vydání: 2000
Předmět:
Zdroj: The American Journal of Cardiology. 85:1362-1364
ISSN: 0002-9149
DOI: 10.1016/s0002-9149(00)00770-0
Popis: P lacement of intracoronary stents during percutaneous transluminal coronary angioplasty (PTCA) decreases the morbidity of acute closure,1 the shortterm requirement for repeat revascularization by achieving a large lumen.2,3 However, stent implantation does not prevent neointimal hyperplasia, and instent restenosis still remains between 20% and 30%.4 Because of favorable initial results, stents are implanted in multivessel PTCA and as a partial revascularization in some patients, especially in elderly and high-risk patients, therefore leaving a potential source of ischemia irrespective of stent restenosis.5 Thus, in an era of cost savings, the ability to localize ischemia noninvasively and detect stent restenosis accurately is crucial in the selection of patients who require further angiographic evaluation. The effectiveness of perfusion scintigraphy in the follow-up of symptomatic and asymptomatic patients with PTCA has been defined by several studies.6–9 However, there are few prospective data regarding the usefulness of exercise perfusion imaging in patients with coronary stent implantation.10 Therefore, the aim of this study was to assess, prospectively, the accuracy of exercise technetium99m (Tc-99m)-tetrofosmin single-photon emission tomography (SPECT) for detecting restenosis after coronary stent implantation. • • • The study group consisted of 97 patients, 74 (76%) men (mean age 58 6 12 years) who, after successful stenting procedures in native coronary arteries, prospectively underwent Tc-99m-tetrofosmin tomographic myocardial scintigraphy and coronary angiography. The average interval between the stent implantation and the scintigraphic myocardial scintigraphy study was 128.4 6 41.0 days (range 88 to 191), whereas that from the scintigraphic study to coronary angiography was 57 6 25 days (range 30 to 64). Because coronary stent implantation in 10 patients was performed in 2 vascular territories, 107 stented vascular territories were included in the evaluation. Patients were excluded with stents in bypass grafts, intervening myocardial infarction, or for revascularization procedures between stent placement and scintigraphic imaging. Prior myocardial infarction ($1 month) corresponding to the stented artery was present in 51 cases. There were 31 patients (60%) with a Q-wave myocardial infarction, and 20 (40%) with a non–Q-wave myocardial infarction. Myocardial viability and residual ischemia assessed by dobutamine echocardiography was documented in most cases (89%) of infarcted territories. At angiography performed before stenting there were 38 patients (39%) with 1-vessel disease, 49 (51%) with 2-vessel disease, and 10 (10%) with 3-vessel disease. Two patients (2%) had previous coronary artery bypass graft surgery. One hundred thirty-five stents (mean length 19 6 7 mm) were implanted in 107 coronary arteries as previously described.11 The distribution of the stented arteries were: 59 (55%) left anterior descending, 20 (19%) left circumflex, and 28 (26%) right coronary artery. Stents were implanted electively in 49% of patients, for suboptimal PTCA in 30% and in bailout due to dissection or vessel closure in 21%. The mean stenosis before stenting was 85 6 12% and after stenting 8 6 7%. Stenting was performed as complete revascularization in 51 patients (53%) and as partial revascularization in the remaining 46 patients (47%). Treadmill testing was performed with the modified Bruce protocol after appropriate pharmacologic washout and according to general standards. Patients underwent 2-day SPECT scintigraphy using Tc-99mtetrofosmin. Representative sections composed of 3 short-axis sections (apical, midventricular, and basal), and of the midventricular vertical long axis combined to assess apical segments, were selected for analysis as described by Garcia et al.12 A 4-point scoring system for segmental uptake of Tc-99m-tetrofosmin was used in which 0 5 normal, 1 5 mildly reduced, 2 5 moderately reduced, and 3 5 severely decreased uptake. Patterns of perfusion defects were separately determined in each segment for rest and stress studies as previously described.13 Defect extension and severity were separately analyzed by 2 observers blinded to each other’s readings. Of the total 832 segments scored, agreement was reached in 790 (95%), whereas in the remaining segments a split decision was resolved by consensus. Myocardial segments were assigned to individual coronary arteries as previously described.13 The observers had knowledge of the vessel of stent implantation but were unaware of the results of the control coronary angiography or the results of exercise testing and clinical findings. Coronary artery stenosis was assessed specifically by 2 experienced cardiologists by means of manual calipers without knowledge of exercise scintigraphic study results. Significant disease From the Institute of Cardiology, Ferrarotto Hospital, University of Catania, Catania, Italy. Dr. Galassi’s address is: Via Antonello da Messina 75, Acicastello 95021, Catania, Italy. E-mail: argal @ ctonline.it. Manuscript received August 6, 1999; revised manuscript received and accepted December 14, 1999.
Databáze: OpenAIRE
Externí odkaz: