Percutaneous coronary interventions in the real world : lessons from the nineties

The use of percutaneous coronary interventions has been expanded tremendously since its introduction in 1977. After the initial experience in the late seventies, the eighties were characterized by mastering elementary techniques in coronary interventions. Still, a common feature of that period was that mostly only single vessel disease could be treated and that a number of complex anatomic situations were not accessible for PCI. Also, the high restenosis rate was one of the features of the eighties. During the nineties, more sophisticated equipment became available (like coronary stents and the possibility for refined physiologic assessment of coronary artery disease). Also, more complex situations and multivessel disease became the area of the interventional cardiologist. Although the state-of-the-art in interventional cardiology is based on large randomized trials and evidence-based medicine, many individual patients do not fit within the frame work of such trials. For this large majority of patients, also the personal experience of the operator is important in the choice of treatment and in providing the best possible care in the every day world. Therefore, in order to have a continuous feed-back and feed-forward upon our way of treating patients, it is necessary to learn from our experience in a systematic way. For that reason, a database was developed which contained all procedure related data concerning patients undergoing percutaneous coronary interventions during the nineties. By analyzing these data, we tried to develop a universally valid view upon complications, mortality, influence of new techniques, and so on. More importantly, such a database also can serve as a quality control instrument. In this thesis, the important issues that were extracted from this database, are described and these lessons from the nineties are summarized. Based upon those lessons, the approach of patients with acute myocardial infarction in the referral area of the Catharina-hospital, was developed. From that database we studied in chapter 2 all patients with diabetes mellitus. In prospectively randomised trials coronary angioplasty is considered an inferior method of revascularization compared with coronary artery bypass grafting. However, this is based on patients with diabetes mellitus and multivessel disease. We studied 97 diabetic patients (9.2%) in the BAAS trial (a prospective randomised trial with 1058 angioplasty patients compared the effects of aspirin alone versus aspirin plus coumarins), of whom 50 patients were randomised to follow-up angiography. Diabetics were identified by treatment with insulin or oral hypoglycaemic medication. Primary end point comprised all cause mortality, myocardial infarction or target-vessel revascularization. The baseline characteristics of the diabetics and nondiabetics were the same except for significant more males and smokers among nondiabetics. At 6 months the minimal luminal diameter was significantly smaller in the diabetics (1.55 ± 0.76 mm versus 1.78 ± 0.66 mm; p=0,01). Diabetics had also more restenosis (41% versus 23%; p=0.003). However, with respect to clinical follow-up, diabetics fared as good as nondiabetics. At 30 days, the primary end point occurred in 5 diabetic patients (5.2%) and 47 nondiabetics (4.9%), (p=0.8), and at 1 year in 17 (17.5%) and in 165 (17.1%), respectively. Univariate hazard ratio for the primary composite endpoint was not statistically significant (p=0.9; 95% CI 0.6-1.7). Multivariate analysis showed that only the presence of a LAD lesion was a significant predictor of the endpoint with a hazard ratio of 1.486 (p=0.01; 95% CI 1.1-2.0). Although diabetics have more restenosis, the short-term follow-up turned out to be as good as in nondiabetics. In Chapter 3 we retrospectively studied if one could prevent recurrent ischaemia or myocardial infarction after non-Q wave myocardial infarction by target vessel revascularization. Some studies have suggested that patients suffering a non-Q wave myocardial infarction have a better prognosis due to less necrosis, which has been disproved in some other studies. Currently, however, there are few data on the immediate and long-term results of PTCA after non-Q wave myocardial infarction. Retrospectively we studied two consecutive groups of patients who underwent PTCA for ischaemia after either a Q wave myocardial infarction (n=175) or a non-Q wave myocardial infarction (n=175). Baseline characteristics and angiographic data were comparable, except that fifteen of the 175 non-Q wave myocardial infarction patients had moderately diminished left ventricular function as opposed to 30 in the Q wave myocardial infarction patients, (p=0.016). There were more total occlusions in the Q wave patients (51% vs 29%; p=0.02). Success rates of the PTCA were similar in both groups (94% vs 97%; p=0.21). At a mean follow-up of 44 months 114 patients (65.1%) of the patients in the Q-wave group remained free from any event compared to 101 in the non-Q wave group (57.8%). Repeat revascularization (surgical or PTCA) was performed in 26 patients (14%) in the Q-wave myocardial infarction group compared to 31 patients (18%) in the non-Q wave myocardial infarction group (p=ns). So, we concluded that the outcome (initial and long-term) after PTCA was similar for patients who suffer from a non-Q wave myocardial infarction group or a Q-wave myocardial infarction group. Therefore: the management strategies after myocardial infarction should not be based on the absence or presence of Q waves at the ECG but rather on the presence of inducible ischaemia. In Chapter 4 we studied the question whether a regional myocardial infarction centre would be an option. Early reperfusion of the occluded coronary artery for patients with an acute myocardial infarction is mandatory for saving myocardial tissue, reduction of complication and mortality. PTCA is more and more often performed in case of an acute myocardial infarction, primary or as a rescue procedure; but coronary angiography is difficult to organise, because of logistic problems, mainly. Only few hospitals have possibilities to perform coronary angiography 24 hours per day We studied the results of all 173 patients who underwent an acute PTCA in our hospital in 1997 (146 primary procedures (84.3%), 27 rescue procedures (15.6%)). It concerned patients with an acute myocardial infarction who where admitted at our hospital or who were referred from hospitals in the region within 6 hours after the start of the symptoms. Admission from these hospitals could be accomplished within 45 minutes in all cases. Most patients underwent this procedure within 6 hours (88.4%). No patient died during the transportation to our hospital. The procedure was successful in 169 out of those 173 patients (98%), and a myocardial infarction was completely prevented (aborted) in 32 of these patients (19%). One hundred and fifteen patients had a Q-wave myocardial infarction (66%). Urgent coronary artery bypass grafting was necessary in 1 patient. Nine patients died in the acute phase, and nine (5%) in the one year follow-up. Within 6 months 3 patients had a repeat myocardial infarction (1.7%), 5 patients underwent re-PTCA, because of restenoses and 7 (4%) underwent elective CABG. Which patients have to be send to a so called myocardial infarction centre? We concluded that patients can be safely transported to a regional myocardial infarction centre in case of primary or rescue PTCA. The in hospital results are satisfactory with an in hospital mortality of 5%. We have to keep in mind that there was a strong selection bias toward patients with a large myocardial infarction, an anterior myocardial infarction or with hemodynamic instability. In Chapter 5 we studied whether eyeball assessment of intermediate coronary stenosis is as good as measuring the fractional flow reserve (FFR). The physiological significance of angiographically severe stenosis (>80% diameter stenosis) or minimal disease