Tim P van de Hoef (Academic Center, AMC Heartcenter, Amsterdam, The Netherlands) and others report in EuroIntervention that pressure-controlled intermittent coronary sinus occlusion (PICSO) may be associated with enhanced myocardial recovery in patients with ST-segment elevation myocardial infarction (STEMI) who have undergone percutaneous coronary intervention (PCI). However, they also report that the feasibility of the system is limited.
The authors state that “optimisation of myocardial perfusion” after primary PCI is considered an “important therapeutic” strategy because the extent of myocardial necrosis is an important determinate of post-infarct cardiovascular events. They add that the PICSO system (Miracor Medical Systems) is designed to intermittently increase “the pressure in the cardiac venous outflow tract using a balloon-tipped catheter introduced to the coronary sinus.” The aim is to redistribute venous blood to the border zone of ischaemic myocardium, enhance washout of deleterious agents from the microcirculation, and to “induce release of vascular growth factors from the venous endothelium; thereby, limiting the extent of myocardial necrosis and enhancing infarct healing.”
The present study, Prepare RAMSES, is the first to evaluate the safety and the feasibility of the system in the setting of acute STEMI. Its goal was to assess the effects of the system on both myocardial necrosis and myocardial function. Patients with STEMI who underwent successful PCI of the left anterior descending artery received PICSO therapy for a maximum of 90 minutes. Van de Hoef et al note that enrolment was halted after the first 30 patients were recruited because of “slow enrolement and a relatively high rate of unsuccessful PICSO procedures.” They add that the therapy was only initiated in 19 of these patients and provided for the intended 90 minutes in only 12. Reasons for not initiating PICSO therapy include inability to engage the coronary sinus, user error, unstable PICSO catheter position prohibiting catheter calibration, and exceeding the PICSO console safety limits.
In patients in whom PICSO therapy was initiated, the median duration of therapy was 88.8 minutes and the median quantity of therapy was 494mmHg. The authors comment that quantity was significantly higher in centres that had previous experience of using the system compared with other centres, despite equivalent duration of therapy.
Van de Hoef et al found that, in a comparison between patients who received “high” PICSO quantity and those who received “low” PICSO quantity, myocardial function “tended to be preserved to a greater extent” in patients with high PICSO quantity. Additionally, high PICSO quantity was associated with favourable trends in the magnitude of infarct size, mircovascular obstruction, and myocardial salvage index. “Even in this small patient cohort, infarct size reduction from baseline to follow-up MRI was significantly higher for high PICSO quantity patients compared with those in whom PICSO quantity was low (41.6±8.2% vs. 21.1±14.1%; respectively; p=0.02), where the reduction in infarct size from baseline to follow-up cardiac MRI showed a significant dose dependency (p=0.008),” the authors comment.
They add that these “favourable trends” for patients with high PICSO quantity were confirmed as compared with their matched control patients (ie. those who had not received PICSO therapy)—“notably, infarct size reduction from baseline to follow-up cardiac MRI was significantly greater in the high PICSO quantity group compared with its matched controls (41.6±8.2% vs. 27.7±9.9%, respectively; p=0.04).
The authors conclude that PICSO therapy may be associated with improved myocardial healing at follow-up in STEMI patients, stating: “If these results can be confirmed using the second-generation PICSO system, which aims to improve feasibility of PICSO, routine application of PICSO in clinical practice may impact on STEMI treatment. However, larger randomised studies are awaited to document whether PICSO improves clinical outcomes.”