| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 1999;68:1475-1477
© 1999 The Society of Thoracic Surgeons
a New York University School of Medicine, New York, New York, USA
b Memorial Mission Hospital, Asheville, North Carolina, USA
c Fairfax Hospital, Falls Church, Virginia USA
Address reprint requests to Dr Grossi, New York University Medical Center, Suite 9-V, 530 First Ave, New York, NY 10028
e-mail: grossi{at}cv.med.nyu.edu
Presented at Evolving Techniques and Technologies in Minimally Invasive Cardiac Surgery, San Antonio, TX, Jan 22–23, 1999.
Abstract
Background. We reviewed the initial patient series of three institutions performing large volume port-access (PA) coronary artery bypass grafting (CABG) to evaluate the efficacy of this new procedure.
Methods. From October 1996 until June 1998, 302 consecutive patients underwent isolated CABG using the PA approach. Patients (mean age 60.7 years) were predominantly male (77.5%) and received a mean of 2.3 distal anastomoses; few were New York Heart Association class III or IV (15.9%). The distribution of the number of grafts was: 76 (25.2%) single, 110 (36.4%) double, 73 (24.2%) triple, and 43 (14.2%) four or more bypass grafts. The Society of Thoracic Surgeons (STS) Database data collection form was used prospectively by all three institutions to define patient risk factors and record outcomes.
Results. Total 30-day hospital mortality was 0.99% compared to the STS-database-model-predicted risk of 1.2%. Complication rates for the PA CABG patients compared with risk-matched morbidity rates from the STS data for CABG alone were: reoperation for bleeding, 3.3% versus 1.9%; ventilatory support more than 1 day, 1.7% versus 3.8%; stroke, 1.7% versus 1.2%; and perioperative transmural myocardial infarction 0% versus 1.3%.
Conclusions. The STS CABG risk-adjusted model demonstrates that the 30-day mortality for patients undergoing PA CABG is lower than predicted for traditional CABG patients (confidence intervals not available). Likewise, the morbidity was low, with minimal ventilatory support, pulmonary complications, and atrial fibrillation. The port-access technique is an acceptable strategy for multivessel bypass grafting.
With the FDA release of Port-Access technology in the fall of 1996 (Heartport Inc, Redwood City, CA), cardiac surgeons were given the option of using these cannulas and catheters for routine cardiac surgery. The potential risks and benefits of widespread application of port-access techniques have not yet been quantified due to the extremely small number of patients included in the original FDA studies. While the technology had been fully tested and documented in the laboratory [1, 2], patient data were not yet available. Although several reports based on small patient groups have been published [3], no large, consecutive patient, multicenter study results are currently available. To determine the efficacy of applying these surgical techniques to a large segment of the coronary artery bypass grafting (CABG) patient population, we conducted a prospective, consecutive, nonrandomized study to evaluate patient mortality for this technique compared to the STS national registry. Also we sought to document patient morbidity associated with this new technique.
Patients and methods
From October 1996 through June 1998, 302 consecutive patients underwent isolated CABG using the port-access technique. The three institutions participating in this study were: Tisch Hospital, NYU School of Medicine, NY, NY; Memorial Mission Hospital, Asheville, NC; and Fairfax Hospital, Falls Church, VA. All three institutions use the STS National Cardiac Database collection form and the Summit Medical Systems (Minneapolis, MN) data-entry engine for prospective data collection. Nurse practitioners prospectively and independently collected the patient data for subsequent analysis.
The port-access surgical technique typically employs a small left anterior thoracotomy. The internal mammary artery is harvested through this incision. Additionally, access to the coronary arteries is achieved for distal anastomosis, as well as access to the ascending aorta for proximal graft placement. Cardiopulmonary bypass with cardioplegic arrest is used. The port-access approach consists of peripheral cardiopulmonary bypass, occlusion of the aorta with a balloon-tipped catheter (Heartport Inc, Redwood City, CA) and cardioplegic arrest by this catheter or by a percutaneously placed coronary sinus catheter. With the heart arrested, the ventricle is sequentially manipulated to provide exposure for the distal artery being grafted. Transesophageal echocardiography is used in all cases to evaluate the aorta and the position of the catheters.
Data analysis of the pooled data set was performed after importing the information into SPSS statistical analysis software (Chicago, IL). The risk-adjusted mortality of this CABG patient population was calculated using the published methodology of the STS risk factors [4]. Since the risk-adjusted mortality model itself has not been published by the STS, which deems the model proprietary information, we extracted the coefficients from the algorithm distributed with the Summit Medical Systems National Database for Cardiac Surgery program.
The incidence of various morbidities reported in the STS database was calculated by two different methodologies. For certain morbidities the STS publishes tables of risk-adjusted incidences [5]. Where these data were available, the incidence of a given morbidity in the STS database was calculated with a risk-matched approach using these tables. For those morbidities without risk stratification, the crude incidence from the STS Primary CAB Alone table was used.
Results
The observed mortality (30-day) in the port-access patients was 0.99% (3/302). The mean predicted risk using the STS risk-adjusted model for this cohort of patients was 1.17% (standard deviation = 1.08; range 0.00% to 8.00%). Mortality risk categorization revealed that 90.4% of the patients had a predicted risk less than or equal to 2.5%, 8.3% of the patients had a predicted risk of 2.5% to 5.0%, and 1.3% had a predicted risk of 5% to 10%. Patient demographics showed a mean ± standard deviation age of 60.7 ± 11.2 years (range 29 to 82), with 77.5% (234) male patients, a mean ejection fraction of 56.6 ± 11.1%, few New York Heart Association class III or IV patients (15.9%; 48), and the following incidences of risk factors: diabetes, 22.8% (69); preoperative inotropes, 0.9% (3); previous cardiac surgery, 2.0% (6); emergent operation, 0.9% (3); peripheral vascular disease, 4.6% (14); renal failure, 1.7% (5); dialysis, 1.3% (4); and shock, 0.3% (1). The patients received a mean of 2.3 distal anastomoses. The distribution of number of grafts was: 25.2% (76), single; 36.4% (110), double; 24.2% (73), triple, and 14.2% (43), four or more bypass grafts.
The incidences of major morbidities is shown in Table 1. The most common serious morbidity encountered in the port-access group was reoperation for bleeding, which occurred in 3.3% of the patients. A permanent neurologic deficit occurred in 1.7%. A nonfatal pulmonary embolus occurred in 1 patient with an antecedent history. Neither deep-wound infections nor perioperative myocardial infections occurred. The incidence of postoperative atrial fibrillation was low (12.6%).
|
This report demonstrates the clinical results achievable with the port-access technique for CABG operations in a large, consecutive patient series. The patient mortality of just under 1% shown in this cohort of 300 patients is comparable to the 1.2% mortality predicted by the STS CABG Alone risk model. While the statistical methodology used here does not allow the calculation of confidence intervals, certainly the mortality data presented here demonstrate that the port-access technique for CABG patients can be performed in selected patients without a major increase in risk. The STS CABG Alone risk model is an exceedingly good model to use for our data comparison because is has been demonstrated to be well-calibrated at the lower end [4]. This ‘low-risk’ end of the model is where the majority of our cohort lie. Having demonstrated this congruous result, it would be appropriate to proceed with a case-match study with the national database to provide more powerful testing of the differences in outcomes of the operative procedures.
The mortality in this patient cohort is also similar to that reported recently by the Port-Access International Registry (PAIR) [6]. In the PAIR’s nonconsecutive series of 583 CAB alone patients, there was a hospital mortality of 1.0%. However, in the PAIR report there was no attempt to perform a risk-adjusted mortality analysis, which makes it difficult to interpret the results.
Morbidities in the STS National Database are reported by the predicted patient mortality risk category. Normalization by use of our patient cohort risk category profile allowed the authors to crudely compare the instant morbidities to those reported in the 1995–1996 CAB STS analysis (STS website) [5]. Reoperation for bleeding occurred in 3.3% of the current cohort compared with 1.9% in the STS analysis. That was the majority morbidity in this cohort and occurred early in our patient series. The incidence of stroke was low (1.7%), occurring mostly in patients greater than 75 years of age. The need for prolonged postoperative ventilation showed only half the incidence recorded in the STS database. The incidence of atrial fibrillation was quite low, perhaps from the avoidance of an atrial suture line.
The appropriateness of the port-access approach for this patient cohort was determined by the six individual surgeons who performed these procedures. Care was taken in both the pre and intraoperative patient evaluations to exclude those patients with significant occlusive peripheral vascular disease or severe intraluminal atheromatous disease of the aorta. Physical exam was carefully undertaken in these patients and additional imaging studies (aortic runoff, computed tomographic scans) were liberally employed. The importance of intraoperative transesophageal evaluation and monitoring of the patients cannot be overestimated. This technique not only monitored the endoclamp position, but at times provided evidence of previously unsuspected aortic pathology.
Currently, with the availability of a port-access cannula and endoclamp for central cannulation, retrograde arterial perfusion is no longer a mandatory component of the port-access technique. Patients with occlusive peripheral vascular disease now are also candidates for this technique. All patients in the initial cohort, however, underwent retrograde perfusion and were carefully evaluated for appropriateness. The low incidence of peripheral vascular complications and aortic injury are a result of this process. The single case of pulmonary embolism occurred in a patient with a history of a previous pulmonary embolism which he failed to reveal to his physicians.
While the goal of all minimally invasive cardiac procedures is to be effective with less trauma and pain, it is mandatory that patient safety not be compromised. Our initial experience with the port-access technique for CABG demonstrates a safety profile comparable to the standard sternotomy approach. Further comparative studies are indicated to quantify the benefits to patients and to better delineate the patient populations where this technique will offer the greatest patient advantages.
Acknowledgments
Supported in part by The Foundation for Research in Cardiac Surgery and Cardiovascular Biology.
Footnotes
All of the authors of this paper have educational consulting agreements regarding beating heart surgery with Medtronic, Inc..
References
This article has been cited by other articles:
|
|
 |
|
  S. Dogan, K. Graubitz, T. Aybek, M. F. Khan, P. Kessler, A. Moritz, and G. Wimmer-Greinecker How safe is the port access technique in minimally invasive coronary artery bypass grafting? Ann. Thorac. Surg., November 1, 2002; 74(5): 1537 - 1543. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Torracca, G. Ismeno, and O. Alfieri Totally endoscopic computer-enhanced atrial septal defect closure in six patients Ann. Thorac. Surg., October 1, 2001; 72(4): 1354 - 1357. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T J Spyt and A C De Souza Minimally invasive therapy and robotics: Treatments in ischaemic heart disease Br. Med. Bull., October 1, 2001; 59(1): 261 - 268. [Full Text] [PDF]
|
|
|
|
 |
|
 S. C. Smith Jr, J. T. Dove, A. K. Jacobs, J. Ward Kennedy, D. Kereiakes, M. J. Kern, R. E. Kuntz, J. J. Popma, H. V. Schaff, D. O. Williams, et al. ACC/AHA guidelines for percutaneous coronary intervention (revision of the 1993 PTCA guidelines): A report of the American College of Cardiology/ American Heart Association Task Force on practice guidelines (Committee to revise the 1993 guidelines for percutaneous transluminal coronary angioplasty) endorsed by the Society for Cardiac Angiography and Interventions J. Am. Coll. Cardiol., June 15, 2001; 37(8): 2239 - 2239. [Full Text] [PDF]
|
|
|
|
|
|
J. P. A. Ioannidis, O. Galanos, D. Katritsis, C. P. Connery, G. E. Drossos, D. G. Swistel, and C. E. Anagnostopoulos Early mortality and morbidity of bilateral versus single internal thoracic artery revascularization: propensity and risk modeling J. Am. Coll. Cardiol., February 1, 2001; 37(2): 521 - 528. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
