Methods

The Florence CTO PCI registry was started in 2003 and includes consecutive patients treated with DES for at least 1 CTO. Details on this registry have been previously published. From this database, we selected a series of consecutive patients who underwent PCI for ≥2 CTOs. CTO was defined as a coronary obstruction with Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 with an estimated duration of >3 months. The duration of the occlusion was determined by the interval from the last episode of acute coronary syndrome or, in patients without a history of acute coronary syndrome, from the first episode of effort angina or by a previous coronary angiography. In patients without a history of angina and who were admitted for an acute coronary syndrome or ST-segment elevation acute MI with a definite identification of the culprit vessel, associated total occlusion of a nonculprit vessel was considered as a chronic occlusion if there was an angiographic evidence of filling the vessel through collaterals. The indication for the percutaneous treatment of CTO was the demonstration of viable myocardium in the territory of the occluded vessel by echographic or scintigraphic provocative tests, whereas no CTO angiographic characteristic was considered as an absolute contraindication to PCI attempt. Thus, patients with long occlusions, extensive calcification, bridging collaterals, a nontapered stump, a side branch at the occlusion site, or a CTO of a venous graft were included.

Patients underwent PCI instead of coronary surgery because of either patient’s preference or the high risk associated with surgery.

Most CTOs were attempted using the anterograde approach and dedicated coronary wires and devices. The type of the DES used was at discretion of the operator. Standard stent implantation techniques, including routine postdilation using final high balloon pressure (≥16 atm) were used. In patients with long occlusions or occlusion in a diffusely diseased vessel, a policy of complete coverage of the disease was adopted using long or multiple stents. Provisional rotational atherectomy was performed if no angioplasty balloon could cross the lesion or the balloon could not dilate the target lesion. Patients with multistaged procedures were included if the second procedure was performed within 2 months from the first intervention. All patients were pretreated with aspirin (300 mg/day) and clopidogrel (loading dose of 600 mg). Aspirin (300 mg/day) was continued indefinitely, whereas clopidogrel (75 mg/day) for at least 12 months. Procedural success was defined as a final diameter stenosis of <30% with a TIMI flow grade 3 of all CTOs and non-CTO–treated lesions without death, non–Q-wave or Q-wave MI, or emergency coronary surgery. Non–Q-wave MI was defined as an increase in creatine kinase-MB fraction of 3× the upper limit of normal or, for patients with elevated values on admission, as a re-elevation of creatine kinase-MB values. Creatine kinase-MB fraction was routinely assessed 12 hours after PCI in all patients or at least 3× every 6 hours in patients with recurrent chest pain. A Q-wave MI was defined as a new Q wave in ≥2 contiguous leads in addition to creatine kinase-MB elevation. Complete revascularization was based on post-PCI angiography and defined as a TIMI flow grade 3 with residual stenosis of <30% on visual assessment in the 3 coronary arteries and their major branches (branch diameter of ≥2 mm). Quantitative coronary angiography of the CTO procedure included the measurement of reference vessel diameter and the minimum lumen diameter immediately after the procedure and during follow-up. Lesion length was assessed from the beginning of the occlusion to distal anterograde or retrograde vessel filling from bridge collaterals or collaterals provided by a coronary artery other than the CTO vessel and using, if necessary, simultaneous contrast medium injection in both right and left coronary arteries. These quantitative angiographic parameters were assessed using a semiautomated edge contour detection computer analysis system (Innova 2100IQ; General Electric Healthcare Technologies, Little Chalfont, Buckinghamshire, United Kingdom). Angiographic in-segment restenosis was defined as >50% luminal narrowing at the CTO segment site including the stent and 5 mm proximal and distal to the stent edges.

The surgical risk was assessed using the logistic EuroSCORE, and high surgical risk was defined as a EuroSCORE of ≥6.

All patients had scheduled clinical and electrocardiographic examinations at 6 months and at 1 and 2 years. All other possible information derived from hospital readmission or by the referring physician, relatives, or municipality live registries were entered into a prospective database. All the eligible patients with successful PCI of at least 1 CTO were scheduled for angiographic follow-up at 6 to 9 months. Unscheduled angiography was allowed on the basis of clinical indication.

The primary end point of the study was cardiac mortality. All deaths were considered cardiac unless otherwise documented. Patients were separated into those with successful PCI of ≥2 CTOs and those with partial PCI success (1 CTO PCI success) or complete CTO PCI failure (no CTO PCI success).

Discrete data are summarized as frequencies, whereas continuous as mean ± SD or median and interquartile range. Chi-square or Fisher’s exact test analysis was used for comparison of categorical variables. A Student t or the Mann-Whitney U test, when appropriate, was used to test differences among continuous variables. Cumulative survival analyses were performed using the Kaplan-Meier method, and the difference between curves was assessed by log-rank test. Multivariate forward stepwise Cox proportional hazards model was performed to evaluate the independent contribution of clinical, angiographic, and procedural variables to cardiac mortality. The following variables were tested: age, gender, diabetes mellitus, previous MI, left ventricular ejection fraction, logistic EuroSCORE, SYNergy between Percutaneous Coronary Intervention with TAXus and Cardiac Surgery trial (SYNTAX) score, complete CTO PCI success, and completeness of revascularization. Hazard ratio and their 95% confidence intervals were calculated. All tests were 2 tailed. A p value <0.05 was considered significant. Analyses were performed using the software packages SPSS 11.5 (SPSS Inc., Chicago, Illinois).

Results

From January 2003 to December 2011, 1,035 patients underwent PCI for at least 1 CTO. Of these patients, 120 (11.6%) underwent PCI for ≥2 CTO lesions for a total of 249 CTOs. CTO PCI was successful in 195 CTOs (78.3%). Procedural success (final diameter stenosis of <30% with a TIMI flow grade 3) in all the attempted CTOs was obtained in 76 patients (63.3%). The procedure was partially successful (at least 1 CTO PCI success) in 34 (28.3%) or completely unsuccessful in 10 (8.3%). Nine patients were treated for 3 CTOs (7.5%): 6 patients had triple successful CTO PCI, whereas in the remaining 3 patients, PCI was partially successful.

Table 1 lists the baseline clinical and angiographic characteristics of the 2 patient groups. Patients with failure or partial success of PCI compared with those with complete PCI success were older (70 ± 9 vs 66 ± 10 years; p = 0.059) and had a greater incidence of previous coronary surgery (36% vs 8%; p = 0.001) and higher EuroSCORE (19.9 ± 19.3 vs 7.0 ± 7.2, p <0.001). Moreover, more patients in the failure or partial success group were at high surgical risk (EuroSCORE of ≥6: 73% vs 37%, p <0.001). There was a trend toward high coronary anatomy complexity (SYNTAX score of ≥33) in patients with failure or partial success of PCI compared with those with complete PCI success (91% and 76%, respectively, p = 0.053) Three-vessel disease was observed in about 60% of the cases, with left main involvement in 14 patients (11.6%). Left ventricular ejection fraction of <40% was revealed in 1/2 of the population and was equally distributed in the 2 groups. CTO lesions were located in main branches of the 3 coronary arteries in 78% of cases, whereas in the remaining patients, the occlusions involved side branches supplying large amount of myocardium (>10% of the left ventricle) or venous grafts.

Table 2 lists the procedural characteristics. The length of the occlusion was longer in the group of patients with a failure or partial success CTO PCI compared with that in the complete CTO PCI success group (40 ± 29 and 36 ± 19 mm, respectively; p = 0.034). Most patients of the complete CTO PCI success group had a complete revascularization (96%).

Table 2

Procedural characteristics

Variable	Intervention Success		p
	Partial or None, n = 44 Patients and n = 91 Lesions (%)	Complete, n = 76 Patients and n = 158 Lesions (%)
Occlusion length (mm), mean ± SD	40 ± 29	36 ± 19	0.034
Length of >20 mm	76/91 (83)	128/158 (81)	0.732
Vessel reference diameter (mm), mean ± SD	2.69 ± 0.37	2.77 ± 0.41	0.297
Diameter ≤2.5 mm	29/91 (32)	35/158 (22)	0.091
Rotational atherectomy	2/91 (2)	6/158 (4)	0.491
No. of stents implanted	59	274
Stents/patient	1.34 (n = 37)	3.60 (n = 158)	0.001
After successful intervention minimum lumen diameter (mm), mean ± SD	2.71 ± 0.36	2.79 ± 0.41	0.293
Fluoroscopic time (minutes), median (IQ range)	44 (30–58)	34 (23–44)	0.017
Contrast (ml), median (IQ range)	400 (300–500)	400 (300–500)	0.972
Concomitant nonocclusion vessel PCI	14 (32)	32 (42)	0.330
Completeness of revascularization	0	73 (96)	<0.001

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