Door-to-balloon (DTB) time is an important metric in primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction to optimize clinical outcomes. The aim of this study was to compare the impact of immediate PCI on culprit lesions in patients with ST-segment elevation myocardial infarctions versus diagnostic angiography followed by PCI on DTB times and procedural data at a high-volume tertiary care radial center. All patients who underwent primary PCI <12 hours after symptom onset were studied. Procedural data and all-cause mortality were assessed in all patients. The primary outcome was DTB time. From January 2006 to June 2011, 1,900 patients were included and divided into 2 groups: 562 patients (30%) underwent primary PCI followed by contralateral diagnostic angiography, and 1,338 patients (70%) underwent diagnostic angiography before primary PCI. No significant differences were observed in baseline characteristics. Left anterior descending coronary artery–related ST-segment elevation myocardial infarctions were more often found in patients who underwent PCI first (54% vs 34%, p <0.0001). Overall, there was a reduction of 8 minutes in DTB time between patients who underwent PCI first and those who underwent angiography first (32 minutes [interquartile range 24 to 52] vs 40 minutes [interquartile range 30 to 69], respectively, p <0.0001). After adjustment, immediate PCI remained an independent predictor of DTB time ≤90 minutes (odds ratio 2.42, 95% confidence interval 1.70 to 3.52, p <0.0001). There were no differences in early and late clinical outcomes. In conclusion, a strategy of transradial direct PCI of the infarct-related artery in selected patients before complete coronary angiography was associated with a benefit of 8 minutes in DTB time. Further study is required to determine whether this strategy can favorably affect clinical outcomes.
Primary percutaneous coronary intervention (PCI) is now the gold-standard treatment for patients with acute ST-segment elevation myocardial infarction (STEMI) because it provides faster reperfusion of the infarcted territory compared to thrombolysis therapy. Door-to-balloon (DTB) time is an important metric and a useful marker of quality of care to optimize patients’ outcomes in the setting of primary angioplasty. Many studies have proposed strategies to reduce DTB time before the arrival of a patient in the catheterization laboratory, but few have actually assessed catheterization laboratory–to–balloon time. The radial approach has been associated with better outcomes compared to the femoral approach in acute coronary syndromes, but concerns exist about longer DTB times with the radial approach. Moreover, reasons for mortality reduction after transradial primary PCI compared to the femoral approach remain elusive. In this study, performed at a high-volume tertiary care radial center, we compared 2 different strategies: immediate PCI of the culprit lesion versus contralateral diagnostic angiography followed by primary PCI, with the aim of assessing (1) DTB time and procedural data, and (2) early and late mortality.
Methods
A retrospective analysis was performed on all patients who underwent primary PCI for electrocardiographically diagnosed STEMIs at Quebec Heart and Lung Institute from January 2006 through June 2011. Inclusion criteria were medical consultation <12 hours after symptom onset, chest pain lasting >30 minutes, ST-segment elevation ≥1 mm in ≥2 adjacent electrocardiographic leads, new left bundle branch block, and posterior myocardial infarction. All patients received aspirin, clopidogrel, and heparin before intervention. Bivalirudin and glycoprotein IIb/IIIa inhibitors as adjunctive pharmacotherapy were left to the operators’ discretion. Exclusion criterion was previous coronary artery bypass graft (CABG) surgery.
A total of 2,006 patients were admitted for consideration of primary PCI for confirmed or suspected STEMI during the study period. Of these, we excluded 71 patients because of incomplete records and 35 patients with alternative diagnoses. A total of 1,900 patients met the inclusion criteria and were included in this analysis. Patients were divided into 2 groups: those who underwent primary PCI on the culprit lesion followed by contralateral diagnostic angiography, and those who underwent complete diagnostic angiography before primary PCI. Data concerning demographic, clinical, and procedural characteristics were retrieved from the catheterization laboratory STEMI database and from the procedure logs. Follow-up data were obtained by directly contacting the patients in telephone interviews, by reviewing hospital records, or from referring physicians. For patients lost to follow-up, vital status was obtained by consulting Quebec’s provincial Directeur de l’État Civil registry. All patients provided written informed consent before primary PCI and separate consent for participation in this STEMI registry, which was approved by the local institutional research board.
The primary outcome of this study was DTB time, which was the time from arrival at the hospital until balloon inflation in the culprit artery. Secondary outcomes included all-cause mortality at 30 days and 1 year, referral for CABG surgery, elective PCI of a non-infarct-related artery, achieved Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow, and the left ventricular ejection fraction 3 days after the index procedure. Detailed procedural data were also collected.
Data are expressed as counts and percentages for categorical variables and as mean ± SD or median (interquartile range) for continuous variables. Statistical comparisons were performed using Fisher’s exact tests and Pearson’s test for categorical variables, while Student’s t test, Wilcoxon’s rank-sum test, and analysis of variance were used for continuous variables. A Kaplan-Meier analysis was performed, and the log-rank test was used to compare late survival between the 2 groups. Potential predictors of DTB ≤90 min were selected with stepwise, backward, and forward procedures using logistic regression analyses. Data were analyzed using JMP version 9.0.0 (SAS Institute Inc., Cary, North Carolina). A p value <0.05 was considered statistically significant.
Results
Of the 1,900 patients, 562 (30%) underwent PCI first and 1,338 (70%) underwent angiography first ( Table 1 ). The overall mean age was 62 ± 12 years, and 76% were men. There were no statistically significant differences between the groups relative to baseline characteristics. Follow-up was complete for all patients, with a median of 1.6 years (interquartile range 1.1 to 2.6). The access site was radial in the 2 groups for almost all patients (93%) ( Table 2 ). The left anterior descending coronary artery was more often the culprit artery in patients who underwent PCI first (54% vs 34%, p <0.0001), while the left circumflex artery and the right coronary artery were more often the culprit arteries in those who underwent angiography first (8% vs 16%, p <0.0001, and 37% vs 50%, p <0.0001, respectively). There were no significant differences in contrast volume, procedural time, and intra-aortic balloon pump use between the 2 groups. Although ventriculography was performed more often in patients who underwent PCI first (66% vs 55%, p <0.0001), contrast volume remained similar in the 2 groups.
| Variable | All | PCI First | Angiography First | p Value |
|---|---|---|---|---|
| (n = 1,900) | (n = 562) | (n = 1,338) | ||
| Age (yrs) | 62 ± 12 | 61 ± 12 | 62 ± 12 | 0.42 |
| Men | 1,445 (76%) | 424 (75%) | 1,021 (76%) | 0.68 |
| Height (cm) | 170 ± 9 | 170 ± 9 | 170 ± 9 | 0.20 |
| Weight (kg) | 78 ± 16 | 79 ± 16 | 77 ± 16 | 0.14 |
| Body mass index (kg/m 2 ) | 27 ± 5 | 27 ± 5 | 27 ± 5 | 0.31 |
| Diabetes mellitus treated | 227 (12%) | 61 (11%) | 166 (12%) | 0.35 |
| Hypertension treated | 804 (42%) | 247 (44%) | 557 (42%) | 0.36 |
| Dyslipidemia treated | 749 (39%) | 220 (39%) | 529 (40%) | 0.88 |
| Current smokers | 801 (42%) | 233 (41%) | 568 (42%) | 0.72 |
| Previous PCI | 165 (9%) | 51 (9%) | 114 (9%) | 0.72 |
| Creatinine clearance (ml/min) | 81 ± 26 | 82 ± 26 | 81 ± 27 | 0.32 |
| Cardiogenic shock | 128 (7%) | 39 (7%) | 89 (7%) | 0.84 |
| Previous myocardial infarction | 213 (11%) | 69 (12%) | 144 (11%) | 0.34 |
| Angina pectoris | 248 (13%) | 72 (12%) | 178 (13%) | 0.65 |
| Variable | All | PCI First | Angiography First | p Value |
|---|---|---|---|---|
| (n = 1,900) | (n = 562) | (n = 1,338) | ||
| Access artery | ||||
| Right radial | 1,723 (91%) | 507 (90%) | 1,216 (91%) | 0.67 |
| Left radial | 52 (3%) | 13 (2%) | 39 (3%) | 0.54 |
| Femoral | 143 (8%) | 43 (8%) | 100 (8%) | 0.85 |
| Infarct-related coronary artery | ||||
| Left anterior descending | 755 (40%) | 305 (54%) | 450 (34%) | <0.0001 |
| Left circumflex | 259 (14%) | 46 (8%) | 213 (16%) | <0.0001 |
| Right | 877 (46%) | 208 (37%) | 689 (50%) | <0.0001 |
| Left main | 9 (0.4%) | 3 (0.5%) | 6 (0.4%) | 0.73 |
| Number of coronary arteries narrowed | ||||
| 1 | 1,345 (71%) | 404 (72%) | 941 (70%) | 0.51 |
| 2 | 396 (21%) | 112 (20%) | 284 (21%) | 0.54 |
| 3 | 159 (8%) | 46 (8%) | 113 (8%) | 0.93 |
| Glycoprotein IIb/IIIa inhibitors | 1,357 (71%) | 420 (75%) | 937 (70%) | 0.04 |
| Heparin | 1,195 (63%) | 343 (61%) | 852 (64%) | 0.28 |
| Bivalirudin | 57 (3%) | 17 (3%) | 40 (3%) | 1.00 |
| Ventriculography | 1,104 (58%) | 370 (66%) | 734 (55%) | <0.0001 |
| Contrast volume (ml) | 185 ± 66 | 187 ± 64 | 183 ± 67 | 0.25 |
| DTB time (minutes) | 37 (27–64) | 32 (24–52) | 40 (30–69) | <0.0001 |
| DTB ≤60 minutes | 1,394 (73%) | 448 (80%) | 946 (71%) | <0.0001 |
| DTB ≤90 minutes | 1,647 (87%) | 524 (93%) | 1,123 (84%) | <0.0001 |
| Procedural time (minutes) | 41 ± 21 | 42 ± 22 | 41 ± 21 | 0.47 |
| Fluoroscopy time (minutes) | 12 ± 8 | 11 ± 9 | 12 ± 8 | 0.23 |
| Dose-area product (Gy cm 2 ) | 6,599 (4,272–10,058) | 6,781 (4,267–10,127) | 6,568 (4,277–10,035) | 0.59 |
| Intra-aortic balloon pump | 101 (5%) | 37 (7%) | 64 (5%) | 0.12 |
| Number of catheters used | ||||
| 1 | 2 (0.1%) | 1 (0.2%) | 1 (0%) | 0.50 |
| 2 | 118 (6%) | 13 (2%) | 105 (8%) | <0.0001 |
| 3 | 1,023 (54%) | 260 (46%) | 763 (57%) | <0.0001 |
| >3 | 1,143 (40%) | 274 (49%) | 469 (35%) | <0.0001 |
Three or more catheters per procedure were more often used in patients who underwent PCI first than in those who underwent angiography first (49% vs 35%, p <0.0001; Table 2 ). Yet dose-area product and fluoroscopy time were similar in the 2 groups. It is interesting to note that when ≥3 catheters were used, fluoroscopy time and radiation dose received as assessed by dose-area product were higher than when ≤2 catheters were used ( Table 3 ).
| Variable | Number of Catheters Used | p Value | |||
|---|---|---|---|---|---|
| 1 | 2 | 3 | >3 | ||
| (n = 2) | (n = 118) | (n = 1,023) | (n = 757) | ||
| Fluoroscopy time (minutes) | 20 (14–25) | 7 (5–13) | 9 (6–14) | 10 (7–15) | 0.0002 |
| Dose-area product (Gy cm 2 ) | 6,652 (5,424–7,880) | 4,598 (3,333–7,740) | 6,255 (4,171–9,245) | 7,679 (4,750–11,772) | 0.0004 |
| DTB time (minutes) | 30 (14–46) | 36 (27–58) | 36 (27–63) | 38 (28–66) | 0.39 |
DTB time was significantly reduced in patients who underwent PCI first (median 32 minutes, interquartile range 24 to 52) compared to those who underwent angiography first (median 40 minutes, interquartile range 30 to 69) (p <0.0001), resulting in a median 8 minutes in favor of patients who underwent PCI first. Up to 93% of patients who underwent PCI first had DTB times ≤90 minutes, while only 84% of those who underwent angiography first did (p <0.0001; Figure 1 ). Furthermore, immediate PCI remained an independent predictor of DTB time ≤90 minutes after adjustment (odds ratio 2.42, 95% confidence interval 1.70 to 3.52, p <0.0001).
