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Early discharge after primary percutaneous coronary intervention
  1. Gerrit J Laarman1,
  2. Maurits T Dirksen2
  1. 1Department of Cardiology, King's College Hospital NHS Foundation Trust, London, UK
  2. 2Department of Cardiology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands
  1. Correspondence to Dr Gerrit J. Laarman, Department of Cardiology, King's College Hospital NHS Foundation Trust, Denmark Hill, London SE5 9RS, UK; gjlaarman{at}gmail.com

Abstract

The length of hospital stay after a successful percutaneous coronary intervention (PCI) for acute myocardial infarction is subject of debate. Patients should not be kept in hospital longer than strictly needed in terms of safety, psycho-social reasons, adequate mobilisation and patient comfort. In many tertiary centres with a busy PCI program insufficient bed capacity is an ongoing concern. Moreover, it seems obvious that shorter hospital stay will lead to a significant cost reduction. In order to know if very early discharge after primary PCI is feasible and safe one should identify the events that might threaten the patient as well as the timing of occurrence of such events. As a result a relatively large proportion of patients with a very low risk of early complications can be defined and in those patients very early discharge is indicated.

  • Acute myocardial infarction
  • delivery of care
  • primary percutaneous coronary intervention
  • shortstay
  • STEMI
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Primary percutaneous coronary intervention (PPCI) is now considered the optimal approach to the management of myocardial infarction (MI) with ST-segment elevation when the procedure is performed expeditiously and at a high-volume centre.1–3

During admission after a PPCI the patient has to recover from the MI, has to start mobilisation, and has to receive explanation on what has happened. Furthermore, secondary prevention should started in terms of lifestyle modification and medication (statins, angiotensin-converting enzyme inhibitors, β-blockers, optimal antiplatelet therapy).

Patients should not be kept in hospital longer than needed in terms of safety (prevention of hospital infections), psychosocial reasons, adequate mobilisation and patient comfort. In many tertiary centres with a busy PPCI programme insufficient bed capacity is an ongoing concern and threatens the continuous safeguarded acceptance of new cases of acute infarctions. Moreover, it seems obvious that a shorter hospital stay will lead to a significant cost reduction.

Cost/effectiveness analyses have suggested that, compared with conventional standards, prolonged hospital stay after successful PPCI (or reperfusion with thrombolysis) and an uncomplicated hospital stay of patients with MI is ‘economically unattractive’ and that an early discharge strategy in a selection of patients results in a substantial cost saving.4–6

Early events after PPCI

In order to know whether early discharge after PPCI is safe one should identify the events that might threaten the patient as well as the timing of the occurrence of such events.

The possible events occurring early after PPCI are: (1) cardiac complications (unstable angina pectoris, recurrent infarction, pump failure, supraventricular and ventricular arrhythmias, atrioventricular conduction disturbances, ventricular septal or free wall rupture and acute mitral regurgitation, intraventricular thrombus with systemic emboli and pericarditis); (2) bleeding complications (access site-related bleedings, other bleedings (eg, gastrointestinal), cerebral bleedings, including stroke); (3) renal failure; (4) fever; (5) new onset or worsening of diabetes mellitus; (6) deep vein throm-bosis and pulmonary embolism.

Unstable angina or recurrent infarction could happen in the case of a critical lesion or the rupture of a vulnerable plaque in a vessel segment other than the infarct-related artery or because of (sub-)acute stent thrombosis.

Pump failure might happen in the case of extensive infarction because of an occlusion of a proximal segment in a large coronary artery (most commonly the left anterior descending artery). This is especially the case when reperfusion has failed and/or after a long period of ischaemia. In addition, previous infarctions, jeopardised collateral circulation, left ventricular dysfunction by other causes or significant mitral or aortic valve disease may contribute to pump failure.

Life-threatening arrhythmias such as ventricular tachycardias or ventricular fibrillation predominantly occur in the first minutes to hours after the onset of ischaemia, and seldom occur beyond 24 h in the absence of failed percutaneous coronary intervention or pump failure. Ventricular arrhythmias, ventricular tachycardia and ventricular fibrillation, during the first 48 h have a low predictive value for the recurring risk of arrhythmias over time compared with arrhythmias developing later that are liable to recur and are associated with an increased risk of sudden death.7 8 Patients without symptomatic arrhythmias and those with an ejection fraction of 40% or greater are at such low risk of sudden cardiac death that further testing or prophylactic therapy is not indicated.7

Supraventricular arrhythmias such as atrial fibrillation may occur in the acute phase of the infarction, mostly related to inferoposterior infarctions, and seldom occur beyond 24 h after the onset of the infarction.

Typical complications of MI, such as complete atrioventricular block, ventricular septal or free wall rupture and acute mitral regurgitation have become rare events in the era of immediate mechanical reperfusion therapy.

Very little is known about the exact timing of events in the very early phase after successful PPCI for acute MI, as the literature mainly describes predictors of 30-day mortality. A practical score for risk stratification, which incorporates these predictors, could distinguish low-risk from high-risk patient groups, but is less helpful in decision-making as to when exactly the patient can be discharged.

Assessment of risk of adverse events after PPCI

After reperfusion treatment it is important to identify patients at high risk of further major adverse events such as recurrent acute coronary syndromes or death. Management of the inhospital phase will be largely determined by the final infarct size, the presence or absence of comorbidities and patient demographics. Patients who are asymptomatic and with relatively small myocardial damage may be discharged very early, partic-ularly after a successful and uncomplicated PPCI, whereas patients with large infarcts with subsequent significant left ventricular dysfunction or those at risk of recurrent adverse events may require a prolonged hospitalisation.7

Assessment of left ventricular function by left ventricular angiography in the acute phase or by echocardiography within the first 24–48 h, however, has its limitations. Left ventricular dysfunction may be due to necrosis, stunning, hibernation of viable myocardium or the combination of all three, of which the two latter may improve in time. The timing of further investigations will depend on local facilities and on the success of the PPCI. With the use of PPCI, compared with thrombolysis and conventional treatment, risk assessment before discharge has become of lesser importance due to the fact that the infarct-related coronary lesion has been treated and secured by stent implantation, and the presence or absence of significant lesions in other coronary arteries has been assessed.

Both current US and European guidelines recommend early discharge (within 4 days of admission) in selected patients with uncomplicated acute MI. After the exclusion of certain high(er) risk patients the occurrence of early major adverse events is almost negligible in the first days after admission. Observations from registries and subanalyses from PPCI/thrombolysis studies have identified low-risk patients. Low-risk patients were defined as those who underwent a successful and uncomplicated reperfusion therapy, and none of the following events occurred during hospital stay: recurrent infarction, recurrent (symptoms of) myocardial ischaemia, stroke, cardiogenic shock, heart failure (Killip class >1), coronary artery bypass grafting, or treatment for ventricular tachycardias.9 Moreover, patients should not have pre-existent severe comorbidities or a history of stroke, recent major surgery or malignancy.

Review of the literature

In the early 1990s, some clinical trials suggested the feasibility and the safety of early discharge after acute MI (3–4 days), at least in a selected subgroup of patients.5 10 Patients who had an uncomplicated course to day 4 after successful thrombolysis had a low rate of death and recurrent major adverse events within 30 days.9

The safety and potential beneficial effects of early discharge after successful PPCI, determined by a diameter stenosis less than 30% and a thrombolysis in myocardial infarction (TIMI) flow grade 3 on final angiography in patients has seldom been discussed. Only one prospective randomised trial, the PAMI-II, has been performed to evaluate this. This study showed that it is safe and cost-effective to discharge low-risk patients within 3 days after an uncomplicated hospital stay after PPCI. Subsequent prospective, non-randomised, trials also confirmed the safety of early discharge in a selected low-risk patient population (table 1).6 11–13 There was one prospective (non-randomised) study of patients presenting with a ST segment elevation myocardial infarction (STEMI) in which patients were discharged early irrespective of patient characteristics as long as the PPCI was successful and hospital stay remained uncomplicated.12 That study had few exclusion criteria and resulted in a fairly high number of patients actually being discharged early. Despite some high-risk clinical features, mortality and recurrent adverse events remained low at 1-year follow-up. Similar reassuring data were observed in two prospective studies in low-risk patients, although the number of patients actually being discharged early was low (see table 1).

Table 1

Trials evaluating early discharge after acute myocardial infarction

A post-hoc analysis of all PAMI patients (n=3188) showed that the success of percutaneous coronary intervention was the strongest independent predictor of 30-day major adverse cardiac events.14 This observation was even stronger in combination with fewer than three high-risk clinical factors (age >70 years, Killip class >1, heart rate >100 beats/minute, systolic blood pressure <100 mm Hg, anterior MI, or left bundle branch block).

Taken together, it seemed that even in the pre-PPCI era it had been shown to be safe to discharge low-risk patients within 3–4 days.9 It might be postulated that in the current era of PPCI these low-risk patients may be discharged safely even earlier (48–72 h). Randomised trials of PPCI versus thrombolysis have demonstrated that PPCI-treated patients have reduced rates of recurrent ischaemia and shorter hospital stays.15 16 The ability of PPCI to achieve high rates of TIMI flow grade 3, with a minimal residual stenosis, is likely to be responsible for the low event rates. In those low-risk patients ultra-short hospital stays (discharge <48 h) might be feasible and safe.

De Luca and co-workers17 proposed a practical score for risk stratification in patients with STEMI undergoing PPCI between 1994 and 2001. A prognostic score was built according to 30-day mortality rates in a study population of 1791 patients undergoing primary angioplasty for STEMI. Strongest independent predictors of 30-day mortality at univariate and multivariate analysis included in the score were age, anterior infarction, Killip class, ischaemic time, post-procedural TIMI flow and multivessel disease. This score was able to identify a large cohort (73.4%) of low-risk (score ≤3) patients, with a good discriminatory capacity (c statistic 0.907). The mortality rate was 0.1% at 2 days and 0.2% between 2 and 10 days in patients with a score of 3 or less. These results could be confirmed in a ‘validation set’ of 747 patients undergoing PPCI from 2001 to 2003. In low-risk patients it would take approximately 1097 patients with prolonged hospitalization to save one life. Therefore, an early discharge policy seems to be cost-saving with an acceptable low risk of adverse events.

The authors conclude that their risk score reliably identifies a large group of patients at very low risk, who may safely be discharged early after primary angioplasty. This approach would also result in a substantial cost saving.

Translating trial data to the real world

Analysis of registries and large international clinical trials has pointed out that, in the setting of some, no more than 40% of patients eligible for early discharge were actually discharged early13 18 In the ‘real world’ it is expected to be even more troublesome to discharge all-comers early, particularly because of the underrepresentation of older patients in clinical trials.19

Future perspectives

Defining an acceptable incremental risk of very early discharge is difficult; moreover, early discharge of patients will also depend on society and healthcare systems' willingness to pay for the incremental benefit of providing immediate medical attention to a small number of patients who might develop adverse events after day 3–4. A prospective trial in the current PPCI era focusing on safety and the timing of recurrent adverse events is needed.

Improvements in mechanical reperfusion in PPCI related to early discharge

The literature described is partly obsolete as major changes have been made in PPCI with respect to devices and adjunctive medication.

Stent implantation in this setting is associated with an improvement in both early and late outcomes, compared with balloon angioplasty alone, predominantly as a result of a reduction in early vessel closure and late target-vessel revascularisation.20 21 Whether drug-eluting stents should be given to all patients undergoing PPCI in order to reduce in-stent restenosis and therefore the need for repeated intervention is the subject of controversy,22 23 but it seems to be irrelevant for the very early outcome.

Given the thrombotic origin of acute coronary occlusion, medical and mechanical interventions have been proposed to improve further the initial result of the intervention. Regarding drug treatment, the combination of aspirin, a thienopyridine (clopidogrel or prasugrel), a glycoprotein IIb–IIIa inhibitor (abciximab) or a direct thrombin inhibitor (bivaluridine) has improved early and late clinical outcomes after PPCI for acute MI.24–26 A preferential use of the transradial approach using small-bore guiding catheters for this indication has been proposed to decrease further the incidence of access site-related bleedings.27–29

Regarding mechanical thrombus removal and thereby the prevention of distal embolisation, several treatment strategies have been developed. The studies conducted with these varying devices lead to conflicting results, and therefore the significance of the standard application of these devices is still questionable. Recently, however, a large prospective randomised trial showed a significant benefit in survival after manual thrombus aspiration during PPCI.30

Immediate percutaneous coronary intervention with adjunctive antithrombotic medication and mechanical interventions, together with the early start of secondary preventive measures, including the immediate start of high dosages of statins, has substantially further decreased 30-day mortality in patients with acute MI to less than 2%.

References

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Footnotes

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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