Several challenging issues with regards to the very large amount of percutaneous coronary interventions (PCI) performed and the numerous clinical settings they apply have been addressed by studies published in National Societies of Cardiology Journals (NSCJs).
A large Spanish study showed that survival of patients discharged from hospital after primary PCI for ST-elevation myocardial infarction (STEMI) is quite similar to an age-adjusted population life expectancy (1). However, several differences in success of PCIs and subsequent outcomes have been observed across selected populations. Women included in a Polish nationwide registry have more procedural-related complications after rotational atherectomy and a higher mortality rate (2). A large multinational survey of patients with ACS found similar differences. Women were older than men, with more co-morbidities and were less often revascularized. Compared with men, a higher percentage of women died during follow-up (3). Failure and complications of PCI also worsen clinical outcomes of patients, as reported in another large multinational study. Among patients with a non-ST elevation ACS, 5% experienced at least one complication. Procedural complications were associated with early mortality, acute myocardial infarction (AMI) or stroke (4). More reassuringly, neurological complications following AMI decreased overtime, as reported by the SWEDEHEART registry. Within 10 years the relative risk of ischemic stroke was reduced by 20% at 1-year post AMI. The reduction coincides with the shift of reperfusion therapy from thrombolysis to primary PCI for STEMI and the increased use of evidence-based secondary preventive therapy according to the ESC guidelines (5).
Invasive physiological assessment of coronary lesions with fractional flow reserve (FFR), which is increasingly used, remains a subject of concern. A retrospective analysis of PCI performed in two large volume centers in Portugal showed that it was performed in few patients with either stable CAD or ACS only. However, the release of the 2014 ESC guidelines on myocardial revascularization was followed by 2-fold increase in its adoption (6). The usefulness of instantaneous wave-free ratio (iFR) was assessed using the newly developed Syncvision software to guide the iFR-pullback study and the final decision-making process in long, diffuse, or sequential lesions. Similar results with regards to outcomes of patients, including mortality, AMI, stent thrombosis and target vessel revascularization (TVR) confirmed the safety of this approach too (7).
Distal radial access for PCI is more difficult than conventional radial access. A Turkish study among patients with ACS found no difference between the success rate of both approaches, but distal access was associated with fewer rates of radial spasm and radial occlusion (8). According to the 2018 ESC guidelines, PCI for left main (LM) stenosis is increasingly performed after careful staging of lesions using the SYNTAX score. In a study from Bulgaria showing real world results, successful maximal revascularization was obtained after unprotected PCI of LM in all patients with only few unfavorable clinical outcomes during follow up (9). PCI of LM bifurcation lesions carries a harmful risk of side-branch closure. Two different strategies for provisional side branch interventions have been compared in another study. For non-true bifurcation lesions, a 1-stent technique with (aggressive strategy) or without (conservative strategy) mandatory kissing balloon inflation was applied. For true bifurcation lesions, an elective 2-stent technique (aggressive strategy) was compared to a 1-stent approach followed by a stepwise additional balloon inflation/stenting depending on the residual stenosis of the side branch (conservative strategy). Aggressive and conservative strategies for a side branch provisional stenting had similar results with regards to 1-year TVR (10).
An Egyptian study of patients with STEMI and totally occluded culprit-lesion artery by a heavy thrombus burden compared outcomes of patients in whom thrombus aspiration was performed or not. Thrombus aspiration was associated with better TIMI flow, myocardial blush grade and ST-segment resolution and with reduced 1-month mortality rates (11).
According to the 2018 ESC guidelines on myocardial revascularization, PCI for chronic total occlusions (CTOs) has increasingly been performed using the recommended calculation of the SYNTAX score. This increased rate was clearly seen in a multicenter study from Belgium and Luxembourg in which procedures achieved technical success in 80% of cases. High-volume centers progressively tackled more complex CTOs while keeping success rates stable overtime (12). Another issue of concerns pertains to aorto-ostial CTOs since they are often associated with unfavorable anatomic characteristics and unclear vessel course. Procedural success was achieved in 78% PCI of aorto-ostial CTOs among patients included in a large multinational study. There were only few procedural complications. During follow-up, subsequent TVR and cardiovascular mortality rate remained very low (13).
Treatment of in-stent restenosis is another challenging anatomic scenario. In a 3-year clinical follow-up of patients presenting with bare-metal stent (BMS) in-stent restenosis, a study from Czech Republic showed more favorable outcomes in patients treated with iopromide paclitaxel-coated balloons as compared with those treated with seal-wing paclitaxel-eluting balloons. Major cardiac adverse events and the need for TVR were seen in 2- and 3-fold fewer patients, respectively (14).
A single center study from Turkey reported the results on concomitant PCI or not in transaortic valve implantation (TAVI). Postprocedural complications including pericardial effusion, stroke, major vascular complications, bleeding, and emergency arrhythmias were similar in patients in whom coronary revascularization was performed simultaneously or performed as a staged procedure before or after TAVI. Although 30-day mortality was higher in simultaneously performed than in staged coronary revascularization, 1-year mortality rates were not statistically different (15).
Another new field for percutaneous procedures relates to patients with refractory angina in whom revascularization is not suitable. The coronary sinus reducer (CSR) is intended to relief these disabling symptoms. Among patients in whom the device was implanted in a 5-year Dutch experience, two third of them showed improvements of at least 1 Canadian Cardiovascular Society (CCS) class, and about one half in at least 2 CCS class (16).
As metoprolol was recently shown to reduce progression of ischemic injury in a pig model of STEMI, this effect was assessed in patients with ongoing STEMI. Compared with controls, those who received IV metoprolol before reperfusion had narrower QRS, a lower prevalence of QRS distortion, and a lower sum of ST-elevation, suggesting that IV metoprolol may reduce ischemic injury. The improvement by metoprolol in the ECG parameters correlated with improvement in magnetic resonance imaging (MRI) parameters of infarct size, coronary microvascular obstruction, and left ventricular function (17).
Publications on PCI released by NSCJs provide real world insights on the current evolving challenges in management of patients with CAD across countries whose national cardiac societies are affiliated to the ESC. They highlight the advancements taking place in this dynamic field with ongoing procedural improvements and how ESC guidelines are progressively adopted and implemented in a real-world setting.