Peri-procedural ST segment resolution during Primary Percutaneous Coronary Intervention (PPCI) for acute myocardial infarction: predictors and clinical consequences.

OBJECTIVE: ECG ST segment resolution (STR) has been used to assess myocardial perfusion in STEMI patients undergoing PPCI. However, in most of the studies ECGs recorded at different time points after the actual procedure have been used, limiting the options of therapeutic interventions while the patient is still in the catheterisation laboratory. The aim of this study was to investigate the presence and clinical consequences of intra-procedural STR during PPCI. METHODS: We analysed 12 lead ECGs recorded at the onset and the end of the PPCI procedure, measuring STR in the lead with maximum ST elevation on the initial recording. STR was defined as good when > 50% compared to baseline. RESULTS: Pre and immediately post PPCI ECGs were recorded in 467 STEMI cases whilst the patient was on the catheter lab table. Mean patient age was 63 (+/- 12) years old and 75% were men. Mean duration of symptoms to admission was 3.8 (+/- 3.4) hours and 51% of infarcts were anterior. Good ST resolution at the end of the procedure was seen in 46.5% of patients and was observed more commonly in inferior compared to anterior infarcts (60.1% vs. 32.6%, p<0.001), and in current smokers (53.2% vs. 42.4%, p=0.031). In patients presenting with symptoms for < 4 hours, good STR was more common (74% vs. 66%, p=0.019). Thrombus aspiration was used more frequently in patients who had good STR (88.5% vs 79.8% p=0.011). Patients with good ST resolution had a shorter mean hospital length of stay (3.8 vs. 4.5 days, p=0.009) and a higher left ventricular ejection fraction (49.9% vs. 44.2%, p<0.001) measured by transthoracic echocardiography prior to discharge. CONCLUSION: Good peri-procedural ST resolution was seen in less than half of STEMI patients undergoing PPCI. There were important clinical consequences of good ST resolution. Identification of suboptimal peri-procedural ST resolution could help identify patients who may benefit from new treatments aimed at protecting the microcirculation, whilst the patients are still in the angiography laboratory.

Patterns of ST segment resolution after guidewire passage and thrombus aspiration in primary percutaneous coronary intervention (PPCI) for acute myocardial infarction.

BACKGROUND: ST segment elevation allows the rapid identification of patients with acute myocardial infarction who benefit from emergency reperfusion. Primary percutaneous coronary intervention (PPCI) has emerged as the preferred perfusion strategy for patients presenting with ST segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: We studied the effects of the simple passage of an angioplasty guidewire followed by mechanical thrombus aspiration on the ST segment displacement in 289 patients presenting with acute STEMI. Simple guidewire passage led to a statistically significant fall in the mean ST elevation from 5.9 to 4.9 mm (p<0.001), but the mean ST displacement after subsequent mechanical thrombus aspiration was 4.8 mm, not statistically significantly different from guidewire passage. When compared with simple guidewire passage, thrombus aspiration resulted in more patients achieving more than 50% ST resolution (21.8% vs 15.2%, p=0.009), but a higher proportion had a worsening of ST elevation compared to baseline (19.7% vs 13.5%, p=0.041). CONCLUSIONS: Mechanical thrombus aspiration in acute STEMI did not improve the mean ST resolution compared with simple guidewire passage. Thrombus aspiration increased the proportion achieving 50% resolution but also increased the proportion who had a worsening of ST elevation. These data may help explain some of the uncertainties surrounding the routine use of thrombus aspiration in STEMI and potentially supports the use of 'time to angioplasty guidewire passage' as one of the ways to judge the promptness of PPCI services.

Intermittent jamming of a bileaflet mechanical heart valve in the absence of any extrinsic cause of obstruction.

Structural failure of mechanical heart valves is associated with a high mortality, especially when the valve is implanted in the aortic position. We describe a case of early intermittent dysfunction of a bileaflet mechanical heart valve implanted in a 67-year-old female. Transthoracic and transoesophageal echocardiography demonstrated intermittent jamming of the leaflets in both the open and closed positions in the absence of any obvious obstruction. The reason for the dysfunction was unclear. This intermittent dysfunction was thought to be a result of dynamic distortion of the pivot guards during the cardiac cycle.