Clinical outcomes of patients are typically a key focus of interventionists and cardiologists after the completion of PCIs. Many well-known PCI registries suggested positive outcomes post procedures of PCI patients at different time frames, including discharge, 30 days and longer follow-ups. In a recent report which included 8,687,338 PCIs in the United States from 2003 to 2016, data revealed that although there were significant increase in the proportions of risk factors and the percentage of PCI for MI group (22.8% to 53.1%), risk-adjusted mortality rates just increased slightly after PCI procedures (in STEMI group: 4.9 to 5.3%, p<0.001; in UA or stable angina: 0.8 to 1.0%, p<0.001, but not in NSTEMI group: 1.6 to 1.6%, p=0.18) (Alkhouli, Alqahtani et al. 2020). Data retrieved from the multi-centre Melbourne Interventional Group registry, which included 19,858 procedures in the period of 2005-2013 in Australia, reported relatively low rates of poor cardiac outcomes at discharge, 30 days and 12 months respectively (mortality: 2.3%; 2.4%; 4.4%; MI: 1.1%; 1.9%; 4.5%; major adverse cardiovascular event: 2.2% at 30 days and 13.3% at 12 months). The average length of hospital stay increased from 3.5 days to 4.2 days in the period (Yeoh, Yudi et al. 2017). Similar patterns were seen in the report of the Malaysian National Cardiovascular Database for Percutaneous Coronary Intervention Registry year 2015- 2016. Overall mortality was 2.0%; 2.8% and 6.8% at discharge, 30 days and 1 year respectively. The mean length of hospital stay was 4.3 days and 5.4 days in groups of
patients with heart rate at presentation <90 and >90 beats/minute (National Cardiovascular Disease Database 2016).
Importantly, outcomes post procedures differ significantly according to demographic factors or modifiable risk factors of the PCI patients. To date, demographic factors such as age and sex of coronary patients were reported to be associated with post PCI outcomes. Studies regarding the sex differences in outcomes following PCIs have revealed that male patients have better prognosis after procedures than their female counterparts. For instance, male patients had significantly lower rates of mortality than those of females at discharge (OR 0.58, 95% CI 0.52–0.63, p < .001), 30-day (OR 0.64, 95% CI 0.61–0.66, p = .04), 1-year (OR 0.67, 95% CI 0.60–0.75, p < .001), and at least 2-years follow-ups (OR 0.71, 95% CI 0.63–0.79, p = .005) (Guo, Yin et al. 2018). The major adverse cardiac event (MACE) rate was significantly lower in male patients after initial PCI compared with females in <1-year or at least 1-year (OR 0.67, 95%
CI 0.56–0.80, P < .001 and OR 0.84, 95% CI 0.76–0.93, P < .001) (Guo, Yin et al.
2018). Furthermore, older patients experience worse coronary artery- related outcomes compared to their younger counterparts, which was confirmed in a variety of studies (Topaz, Finkelstein et al. 2017, Numasawa, Inohara et al. 2019). Modifiable cardiovascular risk factors are well-known in accelerating CHD events, while their impact on mortality post PCIs of CHD patients have been confirmed in recent studies.
A total of 100 studies consisting of 884,190 patients included in one meta-analysis, revealing that certain risk subgroups such as diabetes, hypertensive and metabolic syndrome were associated with higher mortality rates following PCIs. For instance, diabetes was associated with significantly higher short and long-term mortality of patients post PCI (Relative risk, RR 2.11; 95% CI: (1.91–2.33) and 1.85; 95% CI:
(1.66–2.06), respectively); groups of hypertensive and metabolic syndrome patients were also reported with significantly higher long-term mortality RR 1.45; 95% CI:
(1.24–1.69) and RR 1.29; 95% CI: (1.11–1.51), respectively (Bundhun, Wu et al.
2015).
Additionally, factors regarding clinical presentation, procedural practices and decision of interventionists and operators in PCI centres have shown considerable impact on outcomes post procedures. The acute MI population, especially the STEMI sub-group, was reported to have worse outcomes than any other groups. These findings were confirmed in a variety of registries across the regions (National Cardiovascular Disease Database 2016, Biswas, Duffy et al. 2018, Han, Park et al. 2018, Alkhouli, Alqahtani et al. 2020). For instance, the overall in-hospital mortality rates reported by the Melbourne Interventional Group in 2005-2016 were 5.8% and 2.3% for STEMI group only and for the whole cohort, respectively. Other worse cardiac outcomes such as MI, major bleeding, stroke, and unplanned CABG surgery were revealed to be higher in STEMI group (Yeoh, Yudi et al. 2017, Biswas, Duffy et al. 2018). Outcomes post PCIs might also be varied due to the type of stents used. A number of systematic reviews and meta-analyses have suggested the advantage of DES in comparison with BMS (Neupane, Khawaja et al. 2019, Piccolo, Bonaa et al. 2019). A study including data of 26,616 patients from 20 randomised trials with a mean of 3.2 years follow-up, DES was proved to reduce the risk of primary outcomes relative to the BMS group (HR 0.84, 95% CI 0.78- 0.90, p<0.001) and this lower risk was found to last up to 1 year. Risks of definite stent thrombosis and target-vessel revascularisation were also reported to be lower in DES group. This finding suggested BMS should no longer be considered the gold standard and supported the use of DES in modern PCI practices in
order to ensure the safety outcomes for PCI patients (Piccolo, Bonaa et al. 2019).
Further, access sites in PCIs have been documented to be associated with procedure- related outcomes for many years. Among these available data, transradial artery access has been proved to be associated with lower bleeding and vascular complications, especially with ACS patients (Mamas, Ratib et al. 2012, Mason, Shah et al. 2018). A recent meta-analysis including 5,055 patients with STEMI reported favourable outcomes of radial approach in comparison with femoral approach. Radial access was associated with risk reduction of mortality (2.7% vs. 4.7%; OR 0.55. 95% CI 0.40- 0.76, p<0.001) and major bleeding (1.4% vs. 2.9%, OR 0.51, 95% CI 0.31-0.85, p=0.01) in these patients (Karrowni, Vyas et al. 2013).
In patients with chronic coronary diseases, PCI has been well recognized in reducing angina symptoms, which provides better quality of life in these patients (Chacko, J et al. 2020). In comparison with optimal medical therapy, the freedom from angina was significantly improved after PCI (RR, 1.20; 95% CI, 1.06-1.37) (Pursnani, Korley et al. 2012). In patients with ACS presentation, PCI has been proved to significantly prevent MACE in these patients (Chen, Barywani et al. 2018, Chacko, J et al. 2020). In a meta-analysis of 46 randomized controlled trials including 37,757 patients, results reported that in the three unstable scenarios of coronary syndromes, PCI was associated with a significant mortality reduction (RR, 0.84 [95% CI, 0.75- 0.93])(Chacko, J et al. 2020).
In comparison with optimal medical therapy, outcomes post PCI were comparable with stable coronary artery disease (Pursnani, Korley et al. 2012, Khan, Singh et al. 2019),
Wong et al. 2019). In one systematic review and meta-analysis including 11,493 participants with chronic total occlusions, medical therapy was significantly associated with higher risk of all-cause mortality (risk ratio (RR) 1.99, 95% CI 1.38–2.86), cardiac mortality (RR 2.36 (1.97–2.84)), and MACE (RR 1.25 (1.03–1.51)) (Li, Wong et al. 2019). In the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, adding PCI together with optimal medical therapy provided greater ischemia reduction in comparison with patients received optimal medical therapy alone (Shaw, Berman et al. 2008).
To summary, outcomes following PCI of CHD patients are positive with relatively low rates of fatal events and these outcomes are associated with a variety of factors.
Understanding the outcomes post PCIs and factors associated with these outcomes is essential for interventionists and operators in enhancing safety and quality of life for CHD patients.