Safety and feasibility of coronary stenting during rescue PTCA: in-hospital outcome.

BACKGROUND: Rescue PTCA is still a debatable procedure and the results published in the literature may not justify routine application of this strategy. AIM: To evaluate the hospital outcome of patients undergoing rescue PTCA with the aim of achieving a complete recanalization of the infarct-related artery (IRA)--residual stenosis assessed with QCA < 30% and TIMI 3 forward flow--obtained with adjuvant coronary stenting when needed. METHOD: From April 1993 to December 1997, 59 consecutive patients underwent rescue PTCA after thrombolysis failure (SK or front-loaded r-tPA, UK) within 6 hours of chest pain onset. All patients had a pre-procedure TIMI 0-1 flow. IRA was the right coronary artery in 23 cases (39%), the left anterior descending in 26 (44%), the left circumflex in 9 (15.3%) and a saphenous vein graft in 1 case (1.7%). In 2 (3.3%) patients, PTCA was not performed (impossibility of crossing the stenosis with the guide-wire). Fifteen patients (26.3%) had a successful procedure (TIMI 3 flow, residual stenosis < 30%) with lone PTCA. Forty-two patients (73.6%) had an intracoronary stent placed (Palmaz-Schatz, Micro-Stent, Multilink, IRIS III): 24 patients (57.1%) for suboptimal angiographic result (TIMI 2 flow, residual stenosis > 30%), 11 patients (26.2%) for dissection, 7 patients (16.7%) for intracoronary thrombosis. All 57 patients had a TIMI 3 flow and a residual stenosis < 30% at the end of the procedure. Mean vessel diameter was 3.22 +/- 0.4 mm, mean balloon size 3.3 +/- 0.4 mm, mean inflation pressure 12 +/- 4 atm, mean residual stenosis 8 +/- 9%. RESULTS: The overall procedure success rate was 96.6%. During hospitalization, three patients (5.1%) suffered subacute reocclusion managed conservatively in one case, with CAGB in another and with re-PTCA in the last one. Three patients (5.1%) had minor vascular complications (groin hematoma) not requiring surgical correction or blood transfusion. No patients died, suffered reinfarction or stroke. All patients were discharged alive and free of angina or clinical heart failure. CONCLUSIONS: Coronary stenting performed in the setting of rescue PTCA leads to a good procedural success rate allowing TIMI 3 flow and low residual stenosis (< 30%). Therefore, when conventional balloon angioplasty is unable to achieve an optimal angiographic result, stenting can be accomplished safely, thereby improving the procedural success rate and allowing a bright event-free survival rate.

Assessment of heart rate variability changes during dipyridamole infusion and dipyridamole-induced myocardial ischemia: a time variant spectral approach.

OBJECTIVES: We sought to evaluate changes in RR interval variability during dipyridamole infusion and dipyridamole-induced myocardial ischemia. BACKGROUND: Myocardial ischemia and the autonomic nervous system can be mutually interdependent. Spectral analysis of RR interval variability is a useful tool in assessing autonomic tone. METHODS: We used a time variant autoregressive spectral estimation algorithm that could extract spectral variables even in the presence of nonstationary signals. Two groups were considered: group A (patients with ischemia, n = 15) with effort or mixed angina, angiographically assessed coronary artery disease and positive exercise and dipyridamole echocardiographic test results, and group B (control subjects, n = 10) with normal exercise and dipyridamole echocardiographic test results. We investigated the following variables: RR interval mean and variance, low frequency (LF) and high frequency (HF) power in normalized units, LF ratio (LF/LFbasal power), HF ratio (HF/HFbasal power) and LF/HF ratio. For each test epoch, we calculated for group A and group B the mean value +/- SE of all indexes considered. Differences due to an effect either of group (ischemic vs. control) or of time (including both drug and ischemia effects) were analyzed by using analysis of variance for repeated measurements. RESULTS: Dipyridamole injection was characterized by a reduction of all spectral components in negative test. The LF ratio was the only variable able to discriminate patients with ischemia from control subjects (p < 0.05), whereas a time effect was evident for both mean RR interval and high frequency power in normalized units (p < 0.05). The LF ratio decreased in group B from 1 +/- 0.00 (basal) to 0.31 +/- 0.22 (peak), and increased in group A from 1 +/- 0.00 to 15.41 +/- 6.59, respectively. Results of an unpaired t test comparing the peak values of the two groups were also statistically significant (p < 0.01). CONCLUSIONS: Our data show that time variant analysis of heart rate variability evidences an increase in the low frequency ratio that allows differentiation of positive from negative test results, suggesting that the electrocardiogram may contain ischemia information unrelated to ST-T variations, even if their enhancement requires a more complex data processing procedure.

Stenting of the Infarct-Related Artery During Complicated Angioplasty in Acute Myocardial Infarction.

The aim of this study was to assess safety and efficacy of coronary stenting as a strategy for improving PTCA suboptimal angiographic result. From March 1993 to December 1995, 104 patients underwent PTCA during acute myocardial infarction. Unplanned coronary stenting was required in 66 pts (63.5%). Procedural success was obtained in 64 pts (97%). Two patients had an unsuccessful stenting procedure: one patient for a suboptimal stent deployment and another for LAD reocclusion requiring emergency CABG (1.5%). Palmaz-Schatz stents were used in 60 pts (91%) and AVE micro-stent in 6 pts (9%). During the hospital course, subacute reocclusion of the vessel occurred in 3 pts (4.6%); one patient underwent a successful rePTCA while the other two underwent CABG. Two patients had vascular groin complications requiring surgical repair of the femoral artery. During hospitalization, one patient underwent elective CABG for early residual myocardial ischemia. At seventy-two hours from PTCA, one patient (1.5%) died as a result of intestinal infarct. Six months survival rate was 98.3% for 59 pts discharged alive from our department. Ten pts were symptomatic during the follow-up: One patient underwent PTCA on another vessel and the other underwent CABG for a multivessel disease. CABG was used in one patient who presented residual silent ischemia in multivessel coronary artery disease. At six months, the first group of patients (18 pts) underwent planned coronary angiography: Vessel patency was present in 17 patients. One patient had an asymptomatic reocclusion of the treated vessel. This study shows a good angiographic result obtained with intracoronary stenting during primary or rescue PTCA of the infarct-related artery. It does not appear to increase major in-hospital adverse events and may reduce the need for surgical revascularization, reducing in-hospital mortality rate and favorably affecting LVEF.

Clinical evaluation of algorithms for ST measurement during exercise test.

HYPOTHESIS: Computer processing of the exercise electrocardiogram (ECG) has many advantages, but the reliability of the analysis algorithms is not easily evaluable. No standard annotated database, nor recommended practice for testing and reporting performance results is available: thus, performance evaluation of such devices can be accomplished only by using a set of unannotated recordings, obtained in clinical practice. We evaluated the accuracy of an original microcomputer-based exercise test analyzer comparing the ST computer output with the measurements obtained by two experienced cardiologists. METHODS: Six hundred ECG strips were randomly selected from the exercise test recordings of 60 patients. The ST shift (at J + 80 ms) was blindly assessed by two observers (with the aid of a calibrated lens) and compared with computer measurements. Correlation coefficients, linear regression equations, percent of discrepant measurements, and 95% confidence limits of the mean error were calculated for all leads, peripheral leads, precordial leads, and "stress-test" leads (II, III, aVF, V4, V5, V6). RESULTS: The computer did not analyze five samples on a total of 600 (0.83%) ECG strips because of excessive noise or signal loss, while 51 (8.5%) were considered unreadable by both observers and 67 (11.2%) were rejected by at least one observer. Correlation between the measurements taken by computer and observer(s) measurements was statistically significant (p < 0.001 for all lead groups), no systematic measurement bias was found, and the mean difference was lower than human eye resolution. CONCLUSIONS: Our algorithms provide results as good as those provided by trained cardiologists in measuring ST changes occurring during exercise test. However, this study did not evaluate whether computer improvement of the signal-to-noise ratio would allow accurate measurements even on cardiologists' uninterpretable ECG. This potential advantage of computer-assisted analysis could be assessed only by using a dedicated exercise test database, in which different patterns of noise are superimposed on noise-free recordings previously annotated for ST level.