ST-elevation myocardial infarction (STEMI) is one of the most critical cardiovascular emergencies, necessitating immediate medical intervention to restore myocardial perfusion and prevent irreversible ischemic damage. The principle of “time is muscle” underscores the urgency in treating these patients: for every minute of delay in reperfusion therapy, a significant number of myocardial cells are lost, contributing to deterioration in morbidity and increased mortality [1]. Among the available treatment options, primary percutaneous coronary intervention (PCI) is the preferred plan of action for reperfusion in STEMI when it can be performed promptly by an experienced team [2].

To optimize outcomes, international guidelines laid by organizations such as the American College of Cardiology (ACC), American Heart Association (AHA), and European Society of Cardiology (ESC) suggest that the door-to-balloon (D2B) time defined as the time from the patient's arrival at the emergency department (ED) to inflation of the balloon in the infarct-related artery should be within 90 minutes in at least 90% of cases [3–5].

Achieving this benchmark requires seamless coordination among emergency physicians, nursing staff, interventional cardiologists, and cath lab personnel. In high-resource countries, methods have been optimized to meet this goal consistently. However, in low- and middle-income countries, like India, various systemic, logistical, and patient-level factors pose challenges in achieving timely PCI [6, 7]. These factors may include lack of EMS pre-notification, delays in triage, diagnostic uncertainty, financial consent issues, or resource limitations.

This clinical audit was conducted at SRM Medical College Hospital and Research Centre, a tertiary care center in Tamil Nadu, India. The aim of this audit was to evaluate institutional performance in achieving the benchmark D2B time of < 90 minutes in STEMI patients treated with primary PCI, by assessing system efficiency, identifying bottlenecks, and implementing targeted strategies for quality improvement. In the era of evidence-based practice and time-sensitive cardiology care, such audits are crucial in aligning clinical operations with global best practices and improving patient outcomes [8].

This retrospective clinical audit was conducted at SRM Medical College Hospital and Research Centre, a tertiary care academic institution in Tamil Nadu, India. The audit aimed to evaluate institutional performance in achieving the recommended D2B time of less than 90 minutes for patients presenting with STEMI and undergoing primary PCI. The audit period spanned from January 1 to December 31, 2024.

All adult patients (≥ 18 years) who presented to the emergency department (ED) with chest pain and a diagnostic electrocardiogram (ECG) showing ST-segment elevation consistent with STEMI were screened. Patients who were confirmed to have STEMI and were treated with primary PCI were included in the audit (Fig. 1). Patients who received thrombolysis instead of PCI, those with contraindications to PCI, or those who experienced delays due to non-system factors such as patient or attender refusal of treatment, or financial consent issues were excluded from the audit.

Data were extracted from the hospital’s emergency records, ECG logs, triage documentation, cardiology notes, and cardiac catheterization lab records. The following key time points were recorded: time of arrival at the ED (door time), time of ECG acquisition, time of PCI decision, and time of balloon inflation in the cath lab. A standardized audit proforma and spreadsheet were used to ensure uniform data collection. All data entries were verified by two independent auditors to ensure accuracy and consistency. The audit benchmark was based on the American Heart Association and European Society of Cardiology guideline recommending that at least 90% of eligible STEMI patients should undergo primary PCI within 90 minutes of arrival at the hospital.

Over the 12-month audit period from January to December 2024, a total of 657 patients presented to the ED at SRM Medical College Hospital and Research Centre with a confirmed diagnosis of STEMI, as established by clinical presentation and 12-lead ECG findings. Of these, 620 patients (94.4%) were deemed suitable for primary PCI and were promptly shifted to the cardiac catheterization laboratory for revascularization. This high proportion reflects effective early identification of STEMI cases and appropriate triage mechanisms in the ED.

Among the 620 patients transferred to the cath lab, 564 patients (91.0%) successfully underwent balloon angioplasty within the recommended D2B time of 90 minutes or less, thus meeting the international benchmark set forth by the ACC and AHA. This result demonstrates that the institution’s STEMI care pathway achieved compliance with the recommended standard in more than nine out of every ten eligible patients. The mean D2B time for this group was approximately 76 ± 9.4 minutes, indicating not only successful target achievement but also relatively consistent performance with limited variation.

However, 56 patients (9.0%) experienced delays with D2B times exceeding the 90-minute threshold (Table 1). A detailed evaluation of these delayed cases revealed multiple contributing factors. The most frequently encountered cause of delay, accounting for 21 cases (37.5%), was related to delays in obtaining informed consent, either due to unavailability of a legally authorized representative, language barriers, or hesitation from family members who needed more time to understand the procedure and associated risks. This highlights a critical bottleneck in the transition from diagnosis to intervention, particularly in a setting where attender decisions often significantly influence timely care delivery.

The second most common category of delay, observed in 18 patients (32.1%), was hemodynamic instability or presence of complex co-morbid conditions such as acute pulmonary edema, severe hypotension, diabetic ketoacidosis, or chronic kidney disease with electrolyte imbalance. These patients required stabilization with intravenous fluids, inotropes, non-invasive ventilation, or dialysis prior to transfer, which contributed to the procedural delay. These delays, while unavoidable in certain clinical situations, underscore the challenge of balancing patient safety with the urgency of reperfusion.

In 17 patients (30.4%), delays were attributable to diagnostic ambiguity or atypical clinical presentation. These included patients with initial non-diagnostic or evolving ECG changes, unclear chest pain symptoms, or overlapping conditions such as pericarditis or left bundle branch block. In these cases, the need for confirmatory investigations and senior cardiologist consult delayed cath lab activation.

Subgroup analysis showed no significant differences in delay rates based on gender or age; however, patients above 65 years were slightly more represented in the delayed group, suggesting a potential link between age-related comorbidities and procedural timing. Time-of-day analysis showed a modest increase in delay rates during night shifts (10.5%) compared to daytime hours (8.2%), likely reflecting logistical constraints and reduced staffing.

Overall, the audit demonstrated that 91% of eligible STEMI patients received PCI within 90 minutes of ED arrival, with only 9% falling outside the benchmark, primarily due to modifiable system and patient-related factors. These findings highlight a robust STEMI care infrastructure while identifying specific opportunities for procedural enhancement and educational intervention.

This clinical audit aimed to assess the efficiency of door-to-balloon (D2B) time in patients with STEMI treated with primary PCI at a tertiary care academic center in India. The results demonstrated that 91% of eligible patients achieved a D2B time of ≤ 90 minutes, meeting the internationally endorsed benchmark recommended by the AHA and ESC, which suggests that at least 90% of STEMI patients should receive PCI within this time frame [1, 2]. This high level of compliance reflects the success of coordinated STEMI care within the institution and aligns with similar outcomes reported by high-performing centers globally [3].

Timely primary PCI is a cornerstone of STEMI management, with extensive evidence showing that reductions in D2B time are associated with lower mortality, smaller infarct size, better left ventricular function, and improved long-term outcomes [4, 5]. De Luca et al. demonstrated that every 30-minute delay in reperfusion therapy is associated with a 7.5% relative increase in 1-year mortality, highlighting the critical importance of system-wide efficiency in reducing treatment delays [6].

The achievement of a 91% compliance rate in this audit indicates the presence of effective interdepartmental collaboration between the emergency department, cardiology team, and catheterization laboratory. Several system enablers likely contributed to this success, including early ECG acquisition in the emergency department, prompt cardiology notification, and prioritization of STEMI cases in the cath lab. Moreover, the audit reflects the benefits of institutional protocols and trained emergency staff who are able to initiate the STEMI care pathway rapidly.

However, despite the overall success, 9% of patients experienced D2B times exceeding 90 minutes. A closer analysis of these delays identified several recurring causes. Most notably, delayed informed consent accounted for more than one-third of the delays. In India and similar healthcare contexts, consent often depends not only on the patient but on family decision-making, which can be delayed by cultural, financial, or logistical barriers. Pinto et al. reported that non-clinical delays such as those due to communication, paperwork, or logistical hesitations are responsible for a substantial portion of treatment delays in STEMI care [7].

Another major factor identified was the need for hemodynamic stabilization before PCI in patients with comorbidities or presenting in cardiogenic shock. These delays are often unavoidable; however, early recognition and rapid initiation of resuscitative care can help minimize lost time. Studies by Menees et al. and Rathore et al. indicate that although shorter D2B times are generally associated with better outcomes, the benefit may be less pronounced in patients with shock or advanced comorbidity, where overall prognosis is more complex [8, 9].

Diagnostic ambiguity also contributed to delayed reperfusion in a subset of patients. These included cases with atypical chest pain, non-diagnostic ECGs, or initial presentations confounded by other pathologies (e.g., left bundle branch block or pericarditis). As highlighted by Widimsky et al., real-time interpretation of ECGs and point-of-care diagnostics, along with access to cardiology consultation, are essential to ensure that subtle or ambiguous STEMI presentations are not missed or delayed [10].

The audit also observed that night-time presentations were marginally associated with increased delays, which is consistent with findings from global registries suggesting off-hour STEMI care is often slower due to reduced staff availability and increased response time [11]. This reaffirms the importance of 24/7 STEMI response teams and reinforced training of on-call personnel.

While the audit successfully identified areas of strength, it also underscored the need for quality improvement strategies. These include implementing prehospital ECGs with electronic transmission, establishing a single-call “Code STEMI” activation protocol, and streamlining consent processes through pre-authorized forms or early patient and family education. Simulation-based drills and interprofessional training have also been shown to reduce cognitive and operational delays and could be incorporated into institutional practice [12].