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Ann Thorac Surg 2005;80:553-558
© 2005 The Society of Thoracic Surgeons
Department of Cardiothoracic Surgery, Cardiovascular Surgeons, PA, Orlando, Florida, and Osceola Regional Medical Center, Kissimmee, Florida
Accepted for publication February 14, 2005.
* Address reprint requests to Dr Allen, 700 W Oak St, Kissimmee, FL 34741 (Email: gary.allen{at}hcahealthcare.com).
| Abstract |
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METHODS: Patients (9 men [90%] and 1 woman [10%]) at a mean age of 66 ± 10 years who were ineligible for coronary artery bypass graft surgery or percutaneous coronary intervention underwent sole therapy transmyocardial laser revascularization using a completely thoracoscopic surgical approach using a holmium:yttrium-aluminum-garnet laser system. Preoperatively, patients had a mean ejection fraction of 0.51 ± 0.09 and a mean angina class of 3.7 ± 0.5.
RESULTS: A mean of 30 ± 2.4 channels were created during mean laser and operative procedure times of 14 ± 2.9 and 133 ± 32 minutes, respectively. Patients were extubated at a mean of 7.6 ± 12 hours and were discharged from the hospital at a mean of 5.4 ± 3.4 days. There were no hospital deaths or major complications. At a mean of 8.4 ± 5.5 months postoperatively, all patients survived and significant clinical improvement with a mean angina class of 1.3 ± 0.5 (p < 0.001).
CONCLUSIONS: A completely thoracoscopic surgical approach is feasible for sole therapy transmyocardial revascularization that affords improved visualization over a limited thoracotomy approach. Limited complications and significant clinical improvement after the procedure were observed. With minimal port manipulation, there is an opportunity for decreased postoperative pain; however, larger studies are warranted to verify this hypothesis.
| Introduction |
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| Dr Allen discloses that he previously had but no longer has any financial relationship with Cardiogenesis.
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Despite the availability of percutaneous coronary interventions (PCI) and coronary artery bypass graft (bypass) surgery, a growing number of patients develop a pattern of diffuse coronary artery disease that is both refractory to medical therapy and not amenable to these treatment modalities [1]. Transmyocardial revascularization (TMR) is a surgical option that, when applied as sole therapy in selected patients within this difficult patient population, is acknowledged by The Society of Thoracic Surgeons Workforce on Evidence-Based Surgery as useful and effective [2]. Among multiple prospective randomized trials with 1 year of follow-up, TMR has provided superior angina relief, improved exercise tolerance, decreased rehospitalizations, and improved event-free survival compared with continued medical management [37]. Continued 3- to 5-year follow-up has demonstrated sustained and significantly superior angina relief after TMR compared with medical therapy [810], with a survival benefit in one of these trials involving sicker class IV patients randomly assigned to TMR [8].
Sole therapy TMR has been conventionally applied using a standard or a limited left anterior thoracotomy, typically at the fifth intercostal space [11]. Whereas 1-year and long-term studies have identified the clinical and quality of life benefits after TMR, patients are nonetheless vulnerable to acute wound morbidities of the thoracotomy surgical approach. Consistent with the development of less invasive approaches in cardiothoracic surgery, initial thoracoscopic techniques have been reported for the TMR procedure [1215]. These techniques support the general feasibility of such an approach. However, they largely represent a limited left anterior thoracotomy with thoracoscopically assisted visualization. To determine the feasibility and midterm benefits of completely thoracoscopic sole therapy TMR using video-assisted surgical techniques (VATS), we collected operative and follow-up data on 10 consecutive patients treated using this technique and report on their hospital course, adverse events, and Canadian Cardiovascular Society (CCS) angina class. Radiographic assessments of postoperative cardiac function and mechanism elucidation were beyond the scope of this initial feasibility study.
| Patients and Methods |
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Surgical Approach
Each patient was intubated with a double-lumen endotracheal tube and received general anesthesia using standard techniques. A transesophageal echocardiography probe was placed in each patient to confirm channel transmurality (by observing left ventricular microbubbles) and to assess left ventricular function. The patient was placed in the left thoracotomy position and "rescue" defibrillator pads were placed. In 3 patients with a history of ventricular irritability, a 100-mg bolus of lidocaine, followed a 2 mg/h maintenance drip was administered. The left lung was then deflated. Four thoracoscopic ports (Ethicon, New Brunswick, NJ) were inserted under direct visualization (Fig 1): (1) an 11-mm port at the sixth intercostal space at the level of the posterior axillary line of the left hemithorax; a 10-mm zero angle thoracoscope was inserted; (2) a 15-mm port at the third intercostal space at the anterior axillary line; this is the main operating site through which endoshear and lasing occurred; (3) an 11-mm port at the third intercostal space, 1 to 2 cm lateral to the sternal edge; this site was primarily used for grasping; and (4) an 11-mm or 15-mm port at the fifth intercostal space, 1 to 2 cm lateral to the sternal edge; this site was primarily used for diaphragm or pericardial retraction, and lasing the anterior surface of the heart.
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Transmural channels were placed approximately 1 cm apart in targeted areas of viable myocardium and were created in groups of three or four, pausing to permit myocardial recovery and to minimize cardiac irritability. The distal tip of the handpiece is designed as a spatial aid to ensure channels were spaced approximately 1 cm2 apart. Handpiece rotation among the ports allowed firm and perpendicular contact between the distal tip and epicardium. As dissection proceeded anteriorly, a second pericardotomy, anterior to the phrenic nerve, was frequently necessary to optimize visualization and access. Adjusting the operating table to the "head down" position aided in visualizing the inferior heart surface. Similarly, rotating the patient toward the right (toward the surgeon) may improve visualization of the anterior heart. If visualization or stabilization are unsatisfactory, an Endo Starfish stabilizer (Medtronic, Minneapolis, Minnesota) may be used. The stabilizer was inserted through port 4 and was placed on the apex of the heart with the assistance of blunt grasping instruments. Once epicardial contact is visually confirmed, 400 mm Hg of suction is applied. Once the stabilizer has been satisfactorily placed, it is fixed into position with the aid of a side rail clamp. Occasionally, a 45-degree or flexible thoracoscope may be helpful.
The sum of these techniques provides substantially improved visualization compared with a limited left anterior thoracotomy. No anticoagulation is administered; as such, bleeding is modest and rarely requires more than a brief period of direct pressure to achieve hemostasis. For persistent bleeding, 5 to 10 mL of autologous platelet rich plasma was topically placed with excellent hemostatic results. At the completion of surgery, a single 19F silastic drain was placed through port 4 and remained in place until drainage fell below 100 mL in 12 hours (typically on postoperative day 1). Fifteen minutes after the completion of lasing, left ventricular ejection fraction was again measured. Patients were treated by standard postcardiotomy protocols. Pain was patient-controlled by morphine anesthesia.
Statistical Analysis
Data were analyzed using a commercially available statistical software package and are expressed as mean ± SD or as a percentage of patients. Mean angina class improvement was analyzed as a continuous variable using Students t test. Statistical significance is considered for p less than 0.05.
| Results |
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There were no reoperations, conversions to thoracotomy, or in-hospital deaths. Two patients with histories of chronic obstructive pulmonary disease demonstrated poor inspiratory effort and required additional positive pressure ventilation and supplemental oxygen (2 to 4 L/min) during their hospitalizations. One patient experienced a nine-beat run of ventricular tachycardia, which self-terminated, and there were no sustained ventricular dysrhythmias in any patient. One patient with a history of chronic atrial fibrillation experienced an acute episode of atrial fibrillation with a maximum heart rate of 130 beats per minute that occurred 5 hours after surgery. This event was successfully treated after 11 hours of medical therapy. The remaining 4 patients with histories of chronic atrial fibrillation remained in their preoperative rhythm with satisfactory rate control throughout their hospital stay. All patients (n = 9 [90%]) previously treated with long-acting nitrates discontinued use of this medication postoperatively. The balance of patients home medications were managed according to their nonanginal cardiac illnesses.
Follow-Up
Patients have been longitudinally followed up postoperatively to a mean of 8.4 ± 5.5 months (range, 1 to 15). The results of an independent angina assessment demonstrated a mean postoperative angina class of 1.3 ± 0.5, which is significantly reduced from the preoperative assessment (3.8 ± 0.5, p < 0.001).
There were no postdischarge early deaths (<30 days), nor have any deaths occurred through the current follow-up period (December 2004). Three patients were readmitted to the hospital since discharge. The first patient treated suffered a subendocardial myocardial infarction 6 months postoperatively, and was successfully treated with medical therapy. Patients 2 and 10 required outpatient thoracentesis on postoperative days 10 and 8, respectively.
Comparative Results
As shown in Table 2, procedural results in this study were generally consistent with prior studies, with several notable differences, however. The total procedure time appears to be increased in the completely thoracoscopic approach owing to the time necessary to place access ports, although the average laser time per number of channels delivered is somewhat reduced. Apparently shorter time to extubation and total hospitalization duration were observed in this single-center completely thoracoscopic approach. The absence of operative deaths in this study compares very favorably with other studies wherein patient selection is limited to hemodynamically stable patients with reasonably well-preserved left ventricular function. The significant angina improvement at follow-up is consistent with prior studies (Fig 2).
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| Comment |
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In the thoracotomy surgical approach, direct visualization of the epicardial areas treated during TMR is limited to the "keyhole" available for viewing. Channels are created using topographic landmarks to assure a therapeutic distribution. In postcardiotomy patients, where the underlying anatomy is obscured by adhesions, lasing through the adherent pericardium may prove hazardous. Attempts to improve visualization through a small incision frequently leads to overretraction of the ribs and subsequent intercostal nerve injury, thus leaving a small incision with no postoperative pain benefit. Employing this "blind" approach leaves the potential risk for perforation of the coronary vessels, which may lead to serious hemorrhage. Furthermore, inadvertent manipulation of patent bypass grafts can lead to graft embolization and cardiac injury. Thus, to optimize the conduct of the procedure, visualization should be maximized. In our experience, the visualization that can be achieved in a VATS approach is superior to that which can be achieved in a thoracotomy, owing to the ability to rotate the scope between ports and the availability of angled scopes for multiple views. Our experience is consistent with that reported by Yim and associates [18], who found that a completely thoracoscopic surgical approach is technically feasible and safe in patients undergoing thoracic reoperation.
It has been hypothesized that the use of a more "limited" open incision might lead to improved patient outcomes in comparison with a standard open incision. This notion is supportable when comparing outcomes after median sternotomy and limited sternotomy or thoracotomy in consecutive patients. For example, Suenaga and associates [19] reported a shorter mean operation time and length of hospital stay in patients undergoing aortic valve replacement using a limited sternotomy (n = 24) as compared with a full sternotomy (n = 18). In a retrospective review of patients undergoing redo bypass surgery of the left anterior descending artery with the left internal mammary artery, Allen and colleagues [20] reported a significantly lower incidence of atrial fibrillation, fewer transfusions required, and shorter mean operation time, time to extubation, and length of hospital stay among patients undergoing a limited thoracotomy (n = 23) as compared with those undergoing partial sternotomy (n = 12). The benefit of a limited versus standard thoracotomy, however, is less clear. In a prospective, randomized controlled study, Lemmer and colleagues [21] compared postoperative pain and pulmonary function in 28 patients after either a limited muscle-sparing thoracotomy or a standard thoracotomy. Whereas patients who received a limited thoracotomy had significantly lower decreases in their pulmonary reserve 24 hours postoperatively, there were no significant differences in postoperative pain, morphine requirements, extubation time, or length of hospital stay [21]. In their review of various thoracotomy approaches, Rogers and Duffy [22] found that no one technique has been found to reduce post-thoracotomy pain syndrome, inferring that the most likely cause is intercostal nerve damage. This is further discussed by others who have reported persistent post-thoracotomy pain syndrome in 42% [23] and 61% [24] of patients at 1 year and in 52% of patients at 2 years [25], outcomes of which were significantly predicted by early postoperative pain.
Thus, the reduction of postoperative pain remains a formidable challenge in the effort to improve patient outcomes while meeting patient expectations for less invasive surgery. There is growing evidence that minimally invasive, VATS approaches can potentially benefit the patient by reducing postoperative pain-related morbidity. Employing VATS-specific maneuvers (for example, flexing the operating table to open the intercostal spaces; avoiding the use of rigid ports; and using smaller [5 mm] telescopes when possible), Yim and colleagues [26] reported an incidence of post-thoracotomy pain syndrome of 15% of patients. In their study of elderly lung cancer patients at Brigham and Womens Hospital, Jaklitsch and associates [27] concluded that recent advances in VATS techniques resulted in decreased recovery times and fewer perioperative complications compared with a standard thoracotomy approach. Similar outcomes were observed by Luketich and associates [28] in lung cancer patients undergoing surgery using either a VATS or thoracotomy approach. In hemodynamically stable patients undergoing urgent thoracic surgery through thoracotomy or VATS, Samiatina and Rubikas [29] reported significantly reduced postoperative treatment duration, complications, and narcotic pain treatment in patients treated using a VATS approach.
Not withstanding these reports, there have been criticisms of VATS. In a retrospective review of hospital records for patients undergoing lung biopsy using a VATS approach (n = 16) or a limited thoracotomy approach (n = 21), Molin and colleagues [30] reported similar operative mortality rates (0%, VATS; 4.8%, thoracotomy), mean lengths of stay (4.8 days, VATS; 5.1 days, thoracotomy), and times to extubation with significantly higher initial VATS procedural costs. Although it has been found that VATS procedures can be performed safely and effectively for a wide variety of surgical indications, it has been cautioned that a learning curve is present, and careful patient selection is essential to optimize results [31, 32]. In a retrospective, age-matched study of lung cancer patients who underwent lobectomy by VATS or thoracotomy [33], significant reductions in immediate postoperative pain and analgesic requirements were observed in VATS patients; however, this difference was lost by day 14. In their longitudinal study of 343 patients who underwent pulmonary resection by thoracotomy (n = 165) or VATS (n = 178), Landreneau and associates [34] reported reduced pain and shoulder dysfunction in VATS-treated patients studied within 1 year postoperatively; however, no difference in patients studied after 1 year. Clearly, further prospective studies to elucidate the comparative benefits of a VATS approach compared with a thoracotomy approach are warranted.
This small series confirms the feasibility, initial safety, and reproducibility of a VATS approach to deliver a complete TMR lesion set. After the initial learning curve period, procedural times were comparable with that for an open chest approach. The majority of patients were extubated in recovery and required minimal medication for pain control. The time to discharge appears to be reduced compared with that observed historically for the open approach, although our small sample precludes a definitive statement in this regard. Postoperative morbidity was modest, and primarily involved noncardiac systems. Prolonged intubation (>24 hours) occurred in 1 elderly patient with a history of chronic obstructive pulmonary disease whose respiratory insufficiency would have more likely than not been further extended if a thoracotomy had been employed. The 20% incidence of symptomatic postoperative pleural effusions was substantially higher than the 9.8% incidence reported by Payne and coworkers [35] who prospectively studied 460 bypass surgery patients. It is difficult to draw any conclusions with regard to this studys higher incidence owing to the relatively small sample size and lack of statistical power, and different patient population. Certainly the fact that 80% of our patients had one or more prior bypass surgeries, and thus an abnormal left hemithorax, may have substantially contributed to this morbidity.
The Ho:YAG laser and commercially available fiberoptic delivery system permits safe intracorporeal device manipulation and lasing and was well suited for this approach in hemodynamically stable patients. Further miniaturization of these instruments promises to reduce access-induced trauma even further. In contrast, the only other commercially available TMR system (carbon dioxide laser; PLC Medical Systems, Franklin, Massachusetts) has a substantially bulkier handprint and employs a direct laser beam within a handpiece that does not allow either easy port access or internal maneuverability. Further multicenter clinical experience to evaluate the VATS approach to the delivery of TMR will be necessary to more fully and objectively evaluate postoperative pain and the initial relative benefits of this approach.
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