Same-Day Discharge After Elective Percutaneous Coronary Intervention for Chronic Total Occlusion in the UK

Objectives. This study examines the safety and feasibility of same-day discharge (SDD) in patients undergoing percutaneous coronary intervention (PCI) to coronary chronic total occlusions (CTOs) and explores independent associations of clinical and procedural characteristics with SDD. Background. While the recently published consensus statements recommend SDD following uncomplicated CTO-PCI, there are limited studies to support this approach. Methods. Data were obtained from the British Cardiovascular Intervention Society (BCIS) registry dataset including 21,330 patients who underwent CTO-PCI electively from 2007 to 2014 in England and Wales. We used multiple logistic regression to evaluate associations with SDD and the BCIS national risk model to examine for safety of SDD. Results. Although overnight stay remained the standard of care following elective CTO-PCI, SDD practice increased from 21.7% to 44.7%. Women were less likely to have SDD than males. SDD was more common in higher CTO volume centers (36.3%) than low CTO volume centers (31.6%), and SDD patient profiles grew riskier over time, with the average age of SDD patients increasing from 61.4 years to 63.2 years. Transradial PCI was most strongly independently associated with SDD (odds ratio [OR], 1.94; 95% confidence interval [CI], 1.80-2.09). Finally, the SDD observed 30-day mortality rates were not different vs those predicted by the BCIS risk model, and SDD was not independently associated with 30-day mortality (OR, 0.54; 95% CI, 0.25-1.15). Conclusion. This study illustrates that SDD is safe in selected patients undergoing CTO-PCI.

J INVASIVE CARDIOL 2022;34(3):E179-E189. Epub 2022 January 28.

Key words: access approach, chronic total occlusion, elective, mortality, percutaneous coronary intervention, same-day discharge, transradial access

Chronic total occlusions (CTOs) are commonly encountered in patients with coronary artery disease, with the prevalence reported between 13%-52% in patients undergoing coronary angiography.^1-3 While historically these were managed medically, particularly when coronary artery bypass was not indicated or not an option, there has been considerable development of techniques to manage these lesions with percutaneous coronary intervention (PCI). As a consequence, contemporary studies have shown increasing PCI success rates of up to 90% in cases with CTO, especially when performed in dedicated CTO-PCI centers with experienced operators, with low rates of major adverse cardiovascular event (MACE), including death (≤0.9%), acute myocardial infarction (MI) (≤2.6%), and target-vessel revascularization (TVR) (≤0.2%).^4-8 Nevertheless, CTO procedures are often complex and represent a high-risk cohort, with CTO procedures known to increase risk in contemporary PCI risk scores.⁹ With the increased complexity of such procedures, there are limited data around optimal monitoring of such patients post procedure and whether they would benefit from overnight stay.

Same-day discharge (SDD) has become the predominant standard of care for elective PCI cases in the United Kingdom (UK),¹⁰ driven mainly by financial pressures,^11,12 patient preference,¹³ and bed capacity. The safety and feasibility of SDD following PCI in patients with stable angina has been examined in several studies, including both randomized controlled trials (RCTs)^13-15 and observational studies.^16-20 However, there are limited clinical outcomes data following SDD in higher-risk elective patients undergoing CTO-PCI. While the most recently published consensus on length of stay following PCI recommends SDD for uncomplicated CTO attempts,²¹ an observational study on SDD following CTO-PCI found no significant difference between SDD and overnight admission in terms of mortality at 24 hours and 30 days post procedure. However, this study only included 144 cases within a single center, 41.7% of which were SDDs.²² Other studies have included multiple complex patient groups, without focusing exclusively on CTO-PCIs.^23,24

In the present study, we used the national British Cardiovascular Interventional Society (BCIS) database to report: (1) the temporal changes of SDD practice following CTO-PCI in England and Wales from 2007 to 2014; (2) the annual prevalence of clinical and procedural characteristics to compare the SDD or admitted patient groups; (3) whether these clinical and procedural characteristics were independently associated with SDD; and (4) the temporal risk trends for SDD patients in terms of 30-day mortality.

The BCIS dataset. The data were obtained from the BCIS database, which includes the vast majority of all PCI procedures undertaken in the UK since 2005 and comprises 113 variables taking into account demographic information, clinical and procedural characteristics, and in-hospital outcomes. Data collection and management are facilitated by BCIS in collaboration with the National Institute of Cardiovascular Outcomes (NICOR), with approximately 100,000 new records currently added annually. All primary operators are obliged to input every PCI undertaken as part of their annual appraisal and revalidation by the General Medical Council. Further information on data quality and accuracy ascertainment has recently been published.²⁵ Each patient’s unique NHS number was linked to the Office of National Statistics to obtain postdischarge mortality information; these are considered robust, as death registration is legally mandated. Institutional research and ethical board approvals were not required for this study as all data were anonymized and routinely collected as part of the national audit.

Study sample and definitions. This was an observational study of patients with CTO who underwent elective PCI in National Health Service (NHS) hospitals in England and Wales from January 2007 to December 2014. CTO was defined as total occlusion of a coronary artery for a duration of at least 3 months. Enabling strategies included dual access, rotational atherectomy, intravascular ultrasound, penetration catheters (including Tornus and Corsair catheters [Asahi Intecc]) and microcatheters (including Finecross [Terumo], CrossBoss [Boston Scientific], and Stingray catheters [Boston Scientific]).

Patients younger than 18 or older than 100 years old were excluded from the study, as were patients with incomplete records of discharge time, mortality, age, and gender. Patients who experienced in-hospital complications prior to discharge or admitting decision were also excluded from the study as these cases would be necessarily admitted for overnight observation. These complications captured adverse arterial and procedural events, bleeding, and adverse hospital outcomes (complications listed in detail in Supplemental Table S1).

Statistical analysis. A bar graph and a line graph were designed to highlight the absolute counts of CTO cases that underwent elective PCI and the prevalence of these cases within the overall elective PCI cohort. A second line graph presents the annual rates of SDD compared with the rates of cases admitted for overnight stay following CTO-PCI, which were also described regionally, applying spatial maps on Primary Care Trusts (PCTs); NHS organizational geographies responsible for authorizing health services and improving public health, managed by the Strategic Health Authorities (SHAs) organizations in England assigned for managing local health services; both organizations were active until 2013.

Differences in patients’ demographic, clinical, and procedural characteristic rates were examined by discharge status. Nominal and ordinal variables were presented by percentages (%) and continuous variables by mean ± standard deviation. Appropriate models were fitted, driven by outcome type, to test for the difference of discharge status on each characteristic; ie, linear regression for continuous outcomes and logistic regression for binary (and pairwise analyses for categories of ordinal or nominal outcomes). A list of these characteristics is provided in Supplemental Table S2. CTO-PCI cases were summed annually per hospital and were further categorized into low, medium, or high volume according to 1st, 2nd, or 3rd quartile, respectively.

Missing values were imputed using multiple imputation by chained equations with 10 different imputed datasets generated. The analyses described below were performed in each of the imputed datasets separately and estimates were then pooled according to Rubin’s rules.²⁶ The imputation models included all of the variables in the dataset, including the outcomes.²⁷

We fitted a multivariable logistic regression model with discharge status as the outcome, on all of the variables described above plus calendar year to evaluate which characteristics were independently associated with SDD. Multicollinearity between the independent variables of the model was examined with variance inflation factors (VIFs). Moreover, we examined for differences in the temporal trends between the observed values of 30-day mortality and the expected mortality rates based on the previously published BCIS risk score model.²⁸ This analysis was performed separately for the SDD and the overnight stay cases. In addition, we fitted a logistic regression model to examine for independent association of SDD and 30-day mortality and adjusted for case mix.

Sensitivity analyses were performed to include the patients who had complications or adverse events during or shortly after the procedure. Further sensitivity analysis involved exclusion of ethnicity from the multivariable logistic regression on SDD.

All analyses were performed using Stata statistical software, version 15, with an alpha level of .05.

A total of 21,330 patients had an elective CTO-PCI procedure between 2007 and 2014, with a downward trend in the absolute numbers of CTO-PCI from 2008, in line with the decrease in elective PCI procedures during this time (Figure 1). Although SDD practice increased from 21.7% in 2007 to 44.7% in 2014 (35.5% overall increase) in patients undergoing CTO-PCI, overnight stay admission remained the predominant practice at every time point as 64.5% of total elective CTO-PCIs were admitted for overnight observation (Figure 2). Figure 3 illustrates substantial heterogeneity in SDD practice over time in England and Wales both between regions and within regions.

Table 1 illustrates the prevalence of demographic and clinical features stratified by discharge status. Males were more likely to be SDD compared with females, as were younger compared with older patients. An increase in the average age of patients in both cohorts was observed, from 61.4 years in 2007 to 63.2 years in 2014 for the SDD cohort, and from 62.8 years to 64.7 years for the overnight stay cases (Supplemental Table S3, Part 1 and Part 2). Also, SDD was more frequently practiced in patients undertaking elective CTO-PCI at high-volume centers (36.3%) compared with patients at low-volume centers (31.6%) (Table 1). Over the study period, comorbid cases and those with significant medical histories were more commonly observed in the overnight stay cohort. These included prior MI (39.2% for SDD vs 43.6% for overnight stay), prior coronary artery bypass grafting (12.8% vs 16.3%), prior PCI (31.9% vs 35.6%), hypertension (59.4% vs 61.6%), peripheral vascular disease (4.7% vs 6.4%), and multivessel disease (29.7% vs 32.0) (Table 1). Patients with renal disease (high creatinine or dialysis) (1.3% for SDD vs 2.3% for overnight stay) were more frequently admitted for overnight observation than SDD, as were those with moderate (30%-50%) (16.9% vs 20.3%) or poor (<30%) (4.3% vs 5.5%) left ventricular ejection fraction (Table 1). Similar results were obtained from the sensitivity analysis, where patients who experienced complications (and therefore were kept for overnight observation) were included in the study (Supplemental Table S4).

We noted changes in the risk factor profiles of patients who underwent CTO-PCI and who were SDD over time, with increasing prevalence of hypertension, valvular heart disease, and stroke, while the prevalence of prior history of coronary artery bypass grafting and previous acute MI decreased (Supplemental Table S3, Part 1 and Part 2).

Table 2 displays the prevalence of the periprocedural characteristics of elective cases that underwent CTO-PCI within the 2 cohorts. We found higher rates of glycoprotein IIb/IIIa inhibitor use in the overnight admitted cohort (3.45% for SDD vs 12.5% for overnight stay), although use decreased sharply in both cohorts, from 5.1% in 2007 to 2.7% in 2014 in the SDD cohort and from 22.3% to 4.6% in the overnight stay cohort (Supplemental Table S5, Part 1 and Part 2). Similarly, patients who underwent PCI by the use of 1 (15.1% for SDD 18.1% for overnight stay), 2 (2.9% vs 4.5%), or more (0.4% vs 1.5%) enabling strategies were more likely to be admitted for overnight stay (Table 2). The prevalence of enabling strategies within the SDD cohort increased over time (Supplemental Table S5, Part 1 and Part 2). Figure 4 displays temporal prevalence of each enabling strategy within the SDD and overnight stay cohorts. Finally, patients who underwent transradial PCI were more likely to be SDD (46.8% vs 27.8%) in contrast with transfemoral PCI (45.1% vs 63.4%) (Table 2). The findings obtained from the sensitivity analysis, where cases that experienced complications during or shortly following PCI were not excluded, did not differ substantially (Supplemental Table S6).

The multivariable logistic regression analysis identified predictors of SDD within the clinical and procedural covariates, which are presented in Table 3, with younger patients (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.99-0.99), females (OR, 0.85; 95% CI, 0.78-0.92), and non-Caucasians (OR, 0.82; 95% CI, 0.75-0.90) significantly more likely to have SDD. Some patient clinical characteristics made them less likely to have SDD, including prior PCI (OR, 0.85; 95% CI, 0.79-0.91), hypertension (OR, 0.89; 95% CI, 0.84-0.96), peripheral vascular disease (OR, 0.80; 95% CI, 0.69-0.92), Q-wave acute MI (OR, 0.79; 95% CI, 0.71-0.88), and significant renal disease (creatinine >200 µmol/L and not on dialysis) (OR, 0.57; 95% CI, 0.43-0.77 for SDD). Some procedural characteristics were also independently associated with reduced prevalence of SDD, ie, use of glycoprotein IIb/IIIa inhibitor (OR, 0.27; 95% CI, 0.23-0.31 for SDD); use of 1 enabling strategy (OR, 0.68; 95% CI, 0.62-0.75 for SDD); use of 2 enabling strategies (OR, 0.52; 95% CI, 0.44-0.62 for SDD); and use of 3 or more enabling strategies during PCI (OR, 0.23; 95% CI, 0.15-0.53 for SDD). Transradial PCI was the factor most predictive of SDD (OR, 1.98; 95% CI, 1.84-2.13), followed by high-volume center (OR, 1.88; 95% CI, 1.64-2.15) and medium-volume center (OR, 1.16; 95% CI, 1.01-1.32). Finally, SDD rates differed widely on a geographical basis, without any regional pattern, and increased overall over time. Similar results were obtained from the sensitivity analysis including patients with complications (Supplemental Table S7, Part 1 and Part 2). When ethnicity was excluded, the model indicated that high cholesterol was also independently associated with SDD (OR, 0.92; 95% CI, 0.86-0.99) (Supplemental Table S8, Part 1 and Part 2), with no other differences to ethnicity included, while patients with high cholesterol were more likely to be Caucasian (Supplemental Table S9).

Mortality rates within 30 days post discharge were lower for the SDD compared with the overnight stay patients (0.12% vs 0.31%; P=.01) (Table 2), while the latter increased from 0.2% in 2007 to 0.5% in 2014) (Supplemental Table S5, Part 1 and Part 2). However, after adjustment for case mix, SDD was not independently associated with 30-day mortality (OR, 0.54; 95% CI, 0.25-1.15) (Table 4). Comparisons of observed and expected 30-day mortality rates, obtained from the BCIS risk model, are displayed in Figure 5. The observed mortality rates were almost consistently lower (except for 2008) than expected for the SDD cases. Similarly, the observed mortality rates for the overnight admitted cases were consistently in line with the expected values. Finally, we found similar temporal changes in the observed rates of 30-day mortality after SDD for the elective CTO-PCI patients and for all of the elective PCIs (Figure 6).

When patients with periprocedural or postprocedural complications were included in the analysis, the association between SDD and 30-day mortality changed to become statistically significant, (OR, 0.36 for SDD; 95% CI, 0.17-0.75) (Supplemental Table S10, Part 1 and Part 2). At the same time, our analysis comparing the observed and predicted 30-day mortality for all overnight stay cases was not significantly different at any year (Figure 5).

This is the first study to explore the clinical and procedural characteristics, temporal trends, and clinical outcomes of patients who underwent CTO-PCI and were subsequently SDD, within a national healthcare system where SDD is currently the standard model of care following elective PCI. The key findings from this study were a doubling in the rates of patients undergoing CTO-PCI who were discharged the same day and, after adjusting for case mix, that this practice was not associated with 30-day mortality.

Although overnight observation remains the predominant standard of care following elective CTO-PCI, our study demonstrates changes in practice with SDD, increasing from 21.7% in 2005 to 44.7% in 2014. We found that patients who were older, had comorbidities (such as prior MI, coronary artery bypass grafting, or PCI, or with renal impairment and high cholesterol) and had more complex CTO-PCI were more likely to be admitted for overnight stay. These factors are associated with mortality and MACE and are used in contemporary risk score models.^9,28-30 Similarly, the use of ≥1 enabling strategies, including dual access site, rotational atherectomy therapy, intravascular ultrasound, and use of penetration catheters or microcatheters, was independently associated with overnight stay. Although these strategies have enabled a significant increase in successful CTO-PCI rates, they are associated with increased risk of periprocedural and in-hospital complications,³¹ which could favor decisions toward overnight stay even in the absence of procedural complications. Nevertheless, our data demonstrate that, over time, higher-risk cases, with comorbidities and complex lesions, were more likely to be SDD, suggesting that increased experience with SDD in specific higher-risk cases that underwent uncomplicated CTO-PCI changed interventionists’ behavior toward SDD. Also, while our findings indicate differences in SDD practice according to ethnicity, this may be due to collinearity with high cholesterol. Our data show that Caucasians are more likely to have increased cholesterol levels compared with non-Caucasians and therefore are less likely to be SDD. The absence of procedural complications increases the likelihood of SDD, as this reflects decreased postdischarge adverse events or death. Access site choice for CTO-PCI remains a challenging issue, with larger femoral arteries providing space and support for larger guiding catheters, allowing facilitation of various CTO techniques and technologies,³² and in many cases are preferred for more complex disease.^33,34 In the present study, we showed that transradial CTO-PCI is the factor most strongly associated with SDD, which may be explained by the fact that patients ambulate earlier, and is associated with decreased rates of access site major bleeding complications compared with transfemoral cases.³⁵ Conversely, we found that glycoprotein IIb/IIIa inhibitor use was the strongest independent predictor associated with overnight stay and their use decreased significantly over time, for both the SDD and the overnight stay cases. Their use may be a surrogate for periprocedural complications, such as slow flow, which would necessitate overnight stay, and maintenance infusions of glycoprotein IIb/IIIa would also by necessity require overnight stay. Finally, glycoprotein IIb/IIIa inhibitors are known to be associated with major bleeding complications, which may encourage operators to monitor patients more closely. These factors are likely to have contributed to the recent recommendation that use of glycoprotein IIb/IIIa inhibitors should be a determinant for overnight observation.²¹

Currently, the J-CTO score is the most commonly used score to evaluate CTO complexity.³⁶ Operator experience is key to determine the success of CTO interventions. The EuroClub consensus suggests that more difficult CTO cases (J-CTO score ≥2) should be referred to high CTO volume centers and dedicated CTO operators, while easier or intermediate procedures (J-CTO score ≤1) can be performed by less experienced operators.³⁷ Although we could not calculate the J-CTO score for the patients included in our study as the BCIS dataset does not contain all the required fields, we observed an independent association between CTO center volume and SDD. This may indicate that high-volume CTO centers with experienced operators may be more comfortable with discharging complex PCI cases on the same day.

Although the success rate for CTO-PCI has increased over time, it remains challenging with increased periprocedural risk of complications compared with simpler elective PCI cases.³⁸ Current reports reveal that 13% of United States (US) and 23% of non-US operators practice SDD following CTO-PCI,³⁹ while the Society of Cardiovascular and Angiographic Intervention (SCAI) consensus on the length of stay following elective PCI²¹ recommends SDD for cases that experienced no complications following a CTO attempt. However, only limited studies have focused on CTO with small sample sizes,²² combining CTO patients with other complex disease cases,^23,24 or including CTO cases within the overall sample size, where the safety of SDD for CTO-PCI alone is unclear. Furthermore, these studies might be biased toward SDD as it would be expected that SDD patients will have better outcomes than those kept overnight because the latter cohort will by definition include the patients who had experienced complications. Nevertheless, even when patients who experienced complications are excluded, the overnight stay cohort will always include higher-risk cases compared with SDD cases, with comparisons between the 2 cohorts resulting in more favorable outcomes for the SDD cases. To try to address this limitation of a simple comparison between cases treated as SDD with those observed overnight, we performed an analysis where comparisons were made between the observed rates of 30-day mortality and those predicted by the BCIS 30-day mortality risk model²⁸ for each cohort separately. We found that the observed 30-day mortality rate for the SDD cohort was in line with the predicted mortality rate as calculated via the BCIS risk mortality score model. These findings add evidence in the literature that SDD is neither inferior nor superior to overnight stay for higher-risk patients who underwent elective CTO-PCI. These findings are of additional importance within the context of the COVID-19 pandemic, where carefully applied SDD would be a safer option for patients, by minimizing exposure to the virus while in hospital.

Study limitations. As an observational study based on routinely collected databases, the present study has various limitations. First, we have no data on intention to treat, ie, prior to PCI operators’ discharge decisions and conclusions on which patients are eligible for SDD a priori cannot be drawn. Second, although 30-day mortality is a widely used outcome to assess safety following PCI, our analysis lacks evidence regarding other adverse long-term outcomes, such as major bleeding complications, stent thrombosis, stroke, and hospital readmissions post discharge. However, mortality outcomes are the most important in terms of safety and increased major adverse events and complications are likely to be accompanied with increased mortality events, which was not observed. Third, the very low mortality event rates captured in the BCIS dataset bring uncertainty regarding the power of the association analysis between SDD and mortality. For the same reasons, the BCIS dataset did not allow us to examine which patients should be considered for SDD or, conversely, which patients should by default be admitted for overnight observation. Fourth, although the BCIS dataset contains a wide variety of information on patients’ demographic, clinical, and procedural features, it does include data on the time of procedure (late procedures might by necessity be admitted for overnight observation), length of the observational period between procedure and discharge decision, CTO-related information (such as use of an antegrade or retrograde approach, vessel calcification, tortuosity, and occlusion length), as well as patients’ information (such as preference, accommodation distance to hospital), and availability of a radial lounge, which is associated with SDD.^40,41 Finally, our findings reflect SDD practice in earlier years (up to 2014) and questions on more contemporary SDD practice cannot be addressed. The most recent extracts of BCIS data (from 2015 onward) are no longer linked to postdischarge mortality outcomes (like data pre-2014) and therefore, this study is unable to repeat the analysis including a more contemporary dataset, as one of the key aims of the paper was to study the safety of SDD practice from CTOs, by tracking 30-day mortality post discharge for those cases that were discharged on the same day compared with those that were kept overnight. Such an analysis cannot be performed on a dataset that only captures in-hospital mortality, which is the case for BCIS data available from 2015 onward.

Our study illustrates that SDD for elective CTO-PCI is safe and has increased in frequency from 2005 to 2014. Determinants of SDD were patients who underwent the procedure transradially and those operated in higher-volume centers. Importantly, the increased frequency of SDD over time revealed an increasing profile toward higher-risk cases, but that was not associated with adverse 30-day mortality outcomes, and remained in line with the predicted rates as calculated by the BSIC risk model.

In summary, in high-volume CTO centers, patients undergoing successful transradial CTO procedures can be safely discharged on the same day without an increased risk of mortality at 30 days. Contemporary randomised clinical trials are needed to examine which patients can be safely SDD following CTO-PCI.

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