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Ann Thorac Surg 2006;82:1446-1450
© 2006 The Society of Thoracic Surgeons

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Original Articles: Cardiovascular

Off-Pump Revascularization of Chronically Occluded Left Anterior Descending Artery Through Left Anterior Small Thoracotomy: Early and Late Angiographic and Clinical Follow-Up

Department of Clinical Science and Bioimaging, Division of Cardiac Surgery, University "G D'Annunzio," Chieti, Pescara, Italy

Accepted for publication May 4, 2006.

^_* Address correspondence to Dr Di Giammarco, Division of Cardiac Surgery, "S Camillo de Lellis" Hospital, Via Forlanini 50, Chieti, Italy (Email: gabriele.digiammarco1{at}tin.it).

	Abstract

Top Abstract Introduction Patients and Methods Results Comment References

 
BACKGROUND: The aim of this retrospective study was to evaluate the safety and efficacy of left anterior small thoracotomy for treatment of isolated chronic total occlusion of the left anterior descending artery.

METHODS: From November 21, 1994, to December 31, 2002, 143 patients with isolated left anterior descending artery chronic occlusion underwent off-pump surgery through left anterior small thoracotomy. Safety was evaluated analyzing 30-day mortality, major adverse cardiac events, and major complications; efficacy was evaluated analyzing 6-month angiographic results and 12-month survival, freedom from cardiac death, freedom from acute myocardial infarction, either in all areas or in the grafted one, freedom from redo or percutaneous coronary intervention, freedom from target vessel revascularization, and freedom from major adverse cardiac events and from any event. Eight-year outcome was reported as well.

RESULTS: Thirty-day mortality was 0.7% (1 patient). No patient experienced acute myocardial infarction, cerebrovascular accident, or urgent repeat revascularization. One-year survival was 98.6% ± 0.7%; freedom from cardiac death was 99.3% ± 0.7%; freedom from acute myocardial infarction in either all areas or in the grafted one was 100%; freedom from redo or percutaneous coronary intervention or from target vessel revascularization was 99.3% ± 0.7%, and freedom from major adverse cardiac events or any event was 97.9% ± 1.2%. Eight-year survival was 94.9% ± 1.9%; freedom from cardiac death was 96.3% ± 1.6%, from acute myocardial infarction in all or in the grafted area 99.2% ± 0.8%, from redo or percutaneous coronary intervention 94.4% ± 2.1, from target vessel revascularization 97.8% ± 1.3%, from major adverse cardiac events 92.8% ± 2.2%, and from any event 89.5% ± 2.7%. Six months after surgery, 56% of survivors underwent angiographic control, showing a patency rate of 98.2%.

CONCLUSIONS: In our experience, left anterior small thoracotomy operation can be considered a suitable choice for treatment of left anterior descending artery chronic occlusion.

	Introduction

Top Abstract Introduction Patients and Methods Results Comment References

 
Chronic total occlusion occurs in 10% of patients with coronary artery lesions treated by percutaneous coronary intervention (PCI) and can be defined as the obstruction of a native coronary artery with no luminal continuity and with angiographic flow grading 0 or 1 according to the Thrombolysis In Myocardial Infarction study group (TIMI) [1, 2]. The duration of a chronic total occlusion can be established on the basis of clinical data (myocardial infarction, sudden onset or worsening of the symptoms, or proven by previous angiography), and it should last more than 30 days [3].

The TOAST-GISE study [3] demonstrated that chronic total occlusion has to be still considered one of the most important risk factor for early and late PCI failure, either with or without stenting. The interventional treatments of chronic total occlusions are burdened with high rate of early complications, such as coronary perforation/dissection (in 25% of cases) or acute/subacute coronary thrombosis (ranging from 2.1% to 6%), with a 6% incidence of acute coronary syndrome demanding an emergent coronary artery bypass grafting (3.2% of cases) [3–5]. In addition, high 6-month restenosis or reocclusion rate has been always considered the main drawback of PCI treatment of chronic total occlusions. In this scenario, minimally invasive off-pump surgery could play an important role in providing better early and late outcomes.

We, therefore, retrospectively analyzed a group of patients affected by isolated left descending artery (LAD) chronic total occlusion, submitted to left internal mammary artery-to-LAD off-pump revascularization through left anterior small thoracotomy. The aim was to assess the safety and efficacy of the treatment, evaluating 30-day and 12-month clinical outcome along with 6-month angiographic results.

	Patients and Methods

Top Abstract Introduction Patients and Methods Results Comment References

 
From November 21, 1994, to December 31, 2002, 853 patients underwent off-pump surgery through left anterior small thoracotomy, grafting left internal mammary artery to LAD; in 143 cases (16.8%), preoperative angiography showed isolated LAD chronic occlusion. This subset of patients has been considered for this retrospective analysis. Use of our data base was authorized by our Institutional Review Board on October 13, 2004. The authorization waived patient consent.

The mean age was 59 ± 10 years; 11 patients (7.7%) were older than 75 years, and 19 (13.3%) were female. All the patients were symptomatic for angina. The mean grade according to Canadian Cardiovascular Society (CCS) was 2.8 ± 0.6. Twenty-five patients complained of some degree of dyspnea (mean New York Heart Association class was 1.7 ± 0.6).

In 15 cases (10.4%), the left anterior small thoracotomy operation was an emergent procedure. Mean ejection fraction was 60% ± 11%. Sixty-seven patients (46.9%) had a history of anterior acute myocardial infarction. In no case was it recent (less than 3 months); myocardial scintigraphy, preoperatively performed in all of them, demonstrated the presence of myocardial viability in the infracted area. Mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) [6] was 2.7%. Twenty-two patients (15.4%) were affected by diabetes mellitus; in 3 cases (2.1%), a chronic pulmonary disease was present. Fourteen (9.8%) patients showed extracoronary vasculopathy. No patient was on chronic hemodialysis. Patients converted to off-pump surgery through median sternotomy were excluded.

An intramyocardial, calcified, small (less sthan 1.5 mm), or a too medial or too lateral LAD were all considered as anatomical contraindications to this surgical approach.

Surgical Procedure
The anesthesia protocol as well as the surgical technical details were previously reported by us [7, 8].

Clinical Data Collection, Monitoring and Definition
The following set of perioperative data was collected prospectively for all patients undergoing myocardial revascularization at our institution, according to the definitions reported. Mortality included death from any cause. Cardiac mortality included any death from cardiac causes and sudden death. Cerebrovascular accident was defined as global or focal neurologic deficit, diagnosed by a neurologist and confirmed by a brain computed tomography scan. Acute myocardial infarction was defined as enzymatic elevation, electrocardiographic sign of necrosis, new akinetic segments at echocardiogram, ventricular arrhythmias non-K+ related. Major complications were defined as the sum of the following: death from any cause, cerebrovascular accidents, acute myocardial infarction, low output syndrome (need of intra-aortic balloon pump or inotropic drugs, or both, for more than 12 hours), need of mechanical ventilation for more than 24 hours, acute renal failure (postoperative blood creatinine 2.0 mg/dL, with a baseline preoperative value 1.4 mg/dL, or 1 mg/dL higher if preoperative value >1.4 mg/dL), and gastrointestinal complications. Major adverse cardiac events were death, acute myocardial infarction, and target vessel revascularization [9]. Any event included death from any cause, acute myocardial infarction, and redo or PCI.

Follow-Up
All the patients were followed up in our outpatient clinic 3, 6, and 12 months after surgery and at yearly intervals thereafter. The most recent information was obtained calling patients or the referring cardiologist from December 1 to December 31, 2005. Follow-up was 100% complete. Mean follow-up was 92.0 ± 25.6 months (range, 36 to 132).

Statistical Analysis
Continuous variables are expressed as mean value ± SD; otherwise, as frequencies in case of categorical variables. Actuarial results were obtained with the Kaplan-Meier method. The SPSS software (Chicago, Illinois) was used. Any difference with a p value less than 0.05 was considered statistically significant.

	Results

Top Abstract Introduction Patients and Methods Results Comment References

 
Left internal mammary artery was directly grafted to LAD in 94% of cases, whereas in 6% of patients another graft (inferior epigastric artery 4%, saphenous vein graft 2%) was used as left internal mammary artery lengthening.

One patient (0.7%) with preoperative ejection fraction lower than 28% died within the first 30 days from acute left ventricular failure. No patient experienced any acute myocardial infarction or cerebrovascular accident. Two patients showed postoperative acute renal failure, which recovered in 2 days after dopamine infusion. Mean awake and extubation time were 1.0 ± 0.5 hours and 2.0 ± 1.0 hours, respectively. Patients were discharged from the intensive care unit after a mean interval of 7.0 ± 6.0 hours. Mean duration of postoperative in-hospital stay was 3.0 ± 1.0 days. No patient suffered from any wound infection, pneumothorax, or pulmonary infection. Postoperative pain control was achieved in all cases.

Survival
After a mean time interval of 40.5 ± 19.4 months, 6 patients had died, 5 of them from cardiac causes. Of 142 survivors, 1 patient died 6 months after surgery; the 12-month mortality rate was 0.7%. One- and 8-year survival rates were 98.6% ± 0.7% and 94.9% ± 1.9%, respectively; freedom from cardiac death was 99.3% ± 0.7% at 1-year and 96.3% ± 1.6% at 8 years (Fig 1).

View larger version (15K): [in this window] [in a new window]   Fig 1. Eight-year survival (dashed line) and freedom from cardiac death (solid line).

Repeat Revascularization
In 7 patients (4.9%), a repeat revascularization was necessary because of recurrence of angina. In 4 cases (at 36, 46, 71, and 72 months after surgery, respectively) a PCI was added on the circumflex system or right coronary artery because of the progression of a not-significant stenosis (less than 50%) at the time of surgery. The remaining 3 cases were scheduled for redo coronary artery bypass graft surgery in the previously grafted area (at 4, 27, and 54 months, respectively) because of left internal mammary artery-LAD graft failure. None of the remaining survivors became symptomatic after surgery.

One- and 8-year freedom from redo or PCI was 99.3% ± 0.7% and 94.4% ± 2.1%, respectively; freedom from target vessel revascularization (redo or PCI) was 99.3% ± 0.7% and 97.8% ± 1.3% for the same time interval (Fig 2).

View larger version (14K): [in this window] [in a new window]   Fig 2. Eight-year freedom from redo or percutaneous coronary intervention (dashed line) and freedom from target vessel revascularization (solid line).

View larger version (15K): [in this window] [in a new window]   Fig 3. Eight-year freedom from major adverse cardiac events (solid line) and freedom from any event (dashed line).

	Comment

Top Abstract Introduction Patients and Methods Results Comment References

 
Chronic total occlusions represents about 10% of lesions treated by PCI [1]. Although interventional cardiologists have been increasing patient recruitment over the last decades, chronic total occlusion still represents an important challenge because of high restenosis or reocclusion rates [3, 4, 9, 18]. Furthermore, interventional treatment of chronic total occlusion is burdened with a high rate of early complications, such as coronary perforation/dissection in 25% of cases or acute/subacute coronary thrombosis ranging from 2.1% to 6% (Table 1), with a 6% incidence of acute coronary syndrome, demanding an emergent coronary artery bypass grafting in more than 3% of cases [3–5].

Thirty-Day Clinical Results
In our series, 30-day mortality was low (0.7%). Having registered neither Q- or non–Q-wave myocardial infarction or urgent repeat revascularization, the 30-day major adverse cardiac event rate was coincident. Suero and colleagues [19] reported in-hospital results of a cohort of 2,007 patients with chronic total occlusion, with a mortality rate of 1.3% and an incidence of acute myocardial infarction of 2.4%. Urgent repeat revascularization was necessary in 2.4% of cases (0.7% coronary artery bypass graft, 1.5% PCI) leading to in-hospital major adverse cardiac event rate of 3.8%. Although other authors [4, 12–15] reported a very low mortality rate (0% to 0.3%), the in-hospital major adverse cardiac event rate stays higher (5.1% to 7.9%) than the major adverse cardiac event rate reported in this study [3, 5, 13].

Twelve-Month Clinical Results
Table 1 summarizes the late outcome of several series of chronic total occlusions reported in the literature as treated by PCI. Twelve-month mortality rates ranged from 1% to 4.2% [3, 11, 17]. Suero and coworkers [19] reported 10-year survival of 2,007 patients with chronic total occlusion undergoing PCI, showing a survival of 73% in case of PCI success. The analysis of the curve clearly demonstrated that 8-year survival of these patients was close to 80%, definitely lower if compared with 92.8% in series herein reported.

Twelve-month major adverse cardiac event rate ranged from 35% to 48% in case of bare metal stent use [3, 11], decreasing to 4% to 19% in case of drug-eluting stent use [9, 11, 17]. Concerning the 6-month major adverse cardiac event rate, the incidence still remains important (23% to 40% and 16.4% for bare metal stent and drug-eluting stent, respectively) [13, 16, 18]. Before the drug-eluting stent era, the target vessel revascularization rate ranged from 5.3% to 25% [13–16] 6 months after the procedure, increasing to 44% [11] at 12-month follow-up. Drug-eluting stent implantation reduced this incidence to 6.3% to 13% [11, 13, 18].

Hoye and colleagues [9] recently demonstrated that routinary use of drug-eluting stents significantly improves freedom from major adverse cardiac events of chronic total occlusions treated by PCI at 1 year after the procedure (82.1% bare metal stent versus 96.4%, p < 0.05). The same finding was confirmed by Werner and associates [11], who reported 1-year freedom from major adverse cardiac events dramatically lower than that in the Hoye series in either the bare metal stent group (52.1%) or the drug-eluting stent group (87.6%).

The clinical findings reported by the above authors clearly demonstrates that, even if drug-eluting stent use has improved the intermediate outcome of patients with chronic total occlusion undergoing PCI treatment, target vessel revascularization or the major adverse cardiac event rate should be still considered higher if compared with those reported in this study. In fact, of 142 survivors listed in our series, 1 sudden death occurred 6 months after surgery, and 1 patient had to be reoperated on because of early graft failure, thus providing a 12-month target vessel revascularization and major adverse cardiac event rate of 0.7% and 1.4%, respectively, and a freedom from major adverse cardiac event rate of 97.9%. Furthermore, no patients experienced acute myocardial infarction within the first postoperative year.

Six-Month Angiographic Results
A high restenosis and reocclusion rate has been always considered the main drawback of interventional treatment of chronic total occlusions. In fact, the 6-month restenosis and reocclusion rate ranged from 32% to 55% and from 3% to 23%, respectively, in the case of bare metal stents [10–16]. The use of drug-eluting stents has improved the angiographic results, reducing 6-month restenosis and reocclusion rates to 8.0% to 22% and 2% to 8%, respectively [10, 16–19].

In our analysis 6 months after surgery, 79 patients underwent a new angiography to check left internal mammary artery to LAD graft patency. One patient, who complained of angina, showed occlusion of the anastomosis 4 months after surgery, leading to a reocclusion rate of 1.3%.

Study Limitations
The main limitation of this retrospective study is the low percentage of angiographic controls performed 6 months after surgery. In spite of our efforts, we were able to recruit only 56% of patients. That is due partly to the well-known patient reluctance to undergo such an invasive procedure in the absence of symptoms and partly to the cardiologist willingness to save resources for diagnostic or interventional procedures.

In conclusion, although a randomized trial comparing patients with LAD chronic total occlusion undergoing the left anterior small thoracotomy operation or PCI has to be considered mandatory to clarify which treatment should be assigned to this subset of patients, the results of this retrospective study should help the focus on off-pump revascularization, especially if done through a minimal surgical access, as representing a valid option in this case to achieve better clinical results.

	References

Top Abstract Introduction Patients and Methods Results Comment References

 

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Gabriele Di Giammarco Marco Pano Alessandro Di Francesco Michele Di Mauro Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Di Giammarco, G. Articles by Di Mauro, M. Search for Related Content PubMed PubMed Citation Articles by Di Giammarco, G. Articles by Di Mauro, M. Related Collections Coronary disease Related Article