Look ma, no hands!

Historical evolution of robot-assisted cardiac surgery: a 25-year journey

Many patients and surgeons today favor the least invasive access to an operative site. The adoption of robot-assisted cardiac surgery has been slow, but now has come to fruition. The development of modern surgical robots took surgeons close collaboration with mechanical, electrical, and optical engineers. Moreover, the necessary project funding required entrepreneurs, federal grants, and venture capital. Non-robotic minimally invasive cardiac surgery paved the way to the application of surgical robots by making changes in operative approaches, instruments, visioning modalities, cardiopulmonary perfusion techniques, and especially surgeons' attitudes. In this article, the serial development of robot-assisted cardiac surgery is detailed from the beginning and through clinical application. Included are references to the historical and most recent clinical series that have given us the evidence that robot-assisted cardiac surgery is safe and provides excellent outcomes. To this end, in many institutions these procedures now have become a new standard of care. This evolution reflects Sir Isaac Newton's famous 1676 quote when referring to Rene Descartes, "If have seen further [sic] than others, it is by standing on the shoulders of giants".

Application of Artificial Intelligence in Pharmaceutical and Biomedical Studies

BACKGROUND

Artificial intelligence (AI) is the way to model human intelligence to accomplish certain tasks without much intervention of human beings. The term AI was first used in 1956 with The Logic Theorist program, which was designed to simulate problem-solving ability of human beings. There have been a significant amount of research works using AI in order to determine the advantages and disadvantages of its applicabication and, future perspectives that impact different areas of society. Even the remarkable impact of AI can be transferred to the field of healthcare with its use in pharmaceutical and biomedical studies crucial for the socioeconomic development of the population in general within different studies, we can highlight those that have been conducted with the objective of treating diseases, such as cancer, neurodegenerative diseases, among others. In parallel, the long process of drug development also requires the application of AI to accelerate research in medical care.

METHODS

This review is based on research material obtained from PubMed up to Jan 2020. The search terms include "artificial intelligence", "machine learning" in the context of research on pharmaceutical and biomedical applications.

RESULTS

This study aimed to highlight the importance of AI in the biomedical research and also recent studies that support the use of AI to generate tools using patient data to improve outcomes. Other studies have demonstrated the use of AI to create prediction models to determine response to cancer treatment.

CONCLUSION

The application of AI in the field of pharmaceutical and biomedical studies has been extensive, including cancer research, for diagnosis as well as prognosis of the disease state. It has become a tool for researchers in the management of complex data, ranging from obtaining complementary results to conventional statistical analyses. AI increases the precision in the estimation of treatment effect in cancer patients and determines prediction outcomes.

Safe introduction and quality control of new methods in coronary surgery

Introduction:

The first part of the paper analyses off pump coronary bypass surgery (OPCAB), which is compared with traditional on-pump procedures (ONCAB). Furthermore ,the paper evaluates the use of a new automatic device for performance of the proximal anastomosis and finally the effect of intracoronary shunt on myocardial ischemia during OPCAB. The main goal of the paper is to demonstrate the importance of careful clinical studies during introduction of the new techniques in cardiac surgery.

Methods:

Statistical analysis was performed on a large clinical database from Buffalo, NY, USA comparing OPCAB and ONCAB. Subsequently, a sequential controlled clinical study compared patients operated with a new automatic connector device to patients operated with classic suture technique. Finally a randomized study was performed to evaluate the effect of the use of an intracoronary shunt during construction of distal anastomosis.

Results:

The studies from Buffalo demonstrated reduced complications rates in high risk patients when OPCAB techniques were used. The use of connector devices in saphenous venous anastomosis was clearly inferior to standard technique. Intracoronary shunt was found to be beneficial by preventing ischemia.

Discussion:

Numerous studies have studied the results of OPCAB vs ONCAB and although results are variable it seems that OPCAB is advantageous in high risk patients, while in low risk patients there are much less if any benefit. The results of the studies of connector devices caused the product to be taken off the market. The value of shunt in OPCAB was clearly demonstrated by the randomized studies.

Conclusion:

The investigations presented in this paper clearly demonstrates the importance of well-designed studies when new surgical methods are introduced. In the present period of rapid technological development, carefully controlled, un-biased clinical trials are crucial to preserve patient safety and avoid unjustified societal cost.

Cardiac Angio-CT Scan for Planning MIDCAB

Precise evaluation of the cardiac and thoracic anatomy of the patient is mandatory for planning safe minimally invasive direct coronary artery bypass (MIDCAB). Three-dimensional images obtained with a computed tomographic coronary angiography (angio-CT) scan make it possible to accurately visualize the intrathoracic surgical anatomy in order to check the feasibility of the direct exposure of the anatomical structures involved in the surgical procedure. Particular morphological parameters of coronary arteries such as diameter, wall calcification, and intramyocardial position as well as bypass grafts and internal thoracic artery (ITA) displacement can all be precisely defined with this method. We present our preliminary experience using cardiac angio-CT scan as a method for selecting patients for MIDCAB in order to avoid possible surgical complications to minimize the necessity for conversion to the standard surgical approach as well as for choosing the best surgical access.

Creative arterial bypass grafting can be performed on the beating heart

BACKGROUND

To demonstrate that compromise is unnecessary in either the design or performance of beating heart surgery, we report our experience, over 1 year, of total arterial revascularization where composite or creative grafting was utilized.

METHODS

We performed 321 off-pump coronary artery bypass operations, of which, 290 (90%) were done with only arterial conduits. The mean number of distal anastomoses was 2.48, with a range of 1 to 5. There were no aortic anastomoses. One hundred eighty-nine patients (65%) were male, and 101 (35%) were female, with a mean age of 67 years. Comorbidities included chronic renal failure (CRF), 21 (7%); diabetes, 92 (32%); obesity, 68 (23%); hypertension, 212 (73%); chronic obstructive pulmonary disease, 189 (65%); cerebral vascular accident (CVA), 39 (13%); smoking, 164 (56%); and hypercholesterolemia, 151 (52%). The mean ejection fraction was 56%, with a range of 21% to 71%. All procedures were performed with external stabilizers with or without vacuum assist. The complete arterial revascularizations included a T-graft (internal thoracic [ITA]/radial arteries [RA]), 130 (45%); a sequential graft (ITA +/- RA), 118 (41%); a U-graft (coronary-coronary graft perfused by the ITA or right gastroepiploic artery), 5 (2%); an I-graft (ITA/RA), 4 (1%); an X-graft (ITA/RA), 2 (12); and a Y-graft (ITA/RA), 31 (10%).

RESULTS

The postoperative incidence of atrial fibrillation was 80 of 290 (27%); CVA, 5 of 290 (2%); bleeding resulting in take-back, 5 of 290 (2%); CRF, 8 of 290 (3%); deep sternal infection, 4 of 290 (1%); and readmission (30-day) for angina, 4 of 290 (1%). The observed perioperative (30-day) mortality was 9 of 290 (3.1%), with the STS predicted rate of 3.82%.

CONCLUSIONS

Our experience indicates that once the operating surgeon has learned to safely expose the lateral and inferior walls of the heart, the type of conduit and the method of revascularization should be no different than that used with cardiopulmonary bypass. However, we still recommend conventional methods of revascularization (on-pump with saphenous vein conduits) for the ischemic patient.

Coronary revascularization without cardiopulmonary bypass in high-risk patients: a route to the future

Previous reports have demonstrated that reoperative coronary revascularization, advanced age, female sex, and impaired left ventricular dysfunction are independent predictors of operative mortality after coronary artery bypass grafting (CABG). CABG without cardiopulmonary bypass (off-pump CABG) has been proposed as a potential therapeutic alternative in these high-risk patient groups. Despite the substantial learning curve associated with off-pump CABG, early outcomes of off-pump CABG in high-risk patients are better than those associated with the conventional on-pump CABG approach. These results suggest that off-pump CABG is a safe alternative to on-pump CABG in high-risk patients. Randomized prospective studies are needed to validate the results of these initial retrospective reports and to demonstrate the long-term benefits of this approach.

One-year clinical outcome after minimally invasive direct coronary artery bypass

BACKGROUND

Minimally invasive coronary artery bypass (MIDCAB) is a new surgical technique by which the left internal mammary artery is anastomosed under direct visualization to the left anterior descending artery without cardiopulmonary bypass.

METHODS AND RESULTS

We followed all 274 patients who underwent MIDCAB from the time it was introduced at a single center. In-hospital and 1-year clinical events were source-documented and adjudicated. The in-hospital major acute cardiac event rate was 2.2%; this included a 1.1% mortality rate. At 1 year, the respective rates were 7.8% and 2. 5%. When compared with the initial 100 procedures, the subsequent 174 procedures had shorter vessel occlusion times (10+/-5 versus 14+/-6 minutes; P:=0.009), times to extubation (6+/-3 versus 14+/-10 hours; P:<0.001), and lengths of hospital stay (2.1+/-1.9 versus 3. 2+/-3.1 days; P:=0.04). Cumulative 1-year adverse cardiac events were 11% in the initial 100 cases and 6% in the subsequent 174 cases (P:=0.17).

CONCLUSIONS

Excellent clinical results can be achieved with the MIDCAB technique. The clinical adverse event rate may decrease with accumulated experience.

Surgical myocardial revascularization without cardiopulmonary bypass

BACKGROUND

Though coronary artery bypass grafting (CABG) without cardiopulmonary bypass is being performed with increasing frequency, in the absence of adequate angiographic follow-up, safety, reproducibility, and efficacy of the procedure remain doubtful. In this prospective study, we report the results obtained by 100% angiographic follow-up of 96 consecutive patients.

METHODS

A total of 96 patients (age range 33 to 76 years) underwent CABG without cardiopulmonary bypass. Single vessel disease was present in 46 (47.9%) patients, double vessel disease in 31 (32.3%), and triple vessel disease in 19 (19.8%) patients. All patients were operated through a standard midsternotomy and an optimal combination of pharmacological and mechanical methods were used to restrict cardiac movements during anastomosis. All patients underwent coronary angiography before discharge from the hospital.

RESULTS

A total of 160 grafts were placed (range 1 to 4 grafts per patient, average 1.7+/-0.3 grafts per patient). A single graft was placed in 46 patients, double grafts in 38, triple grafts in 10, and quadruple grafts in 2 patients. Various grafts included pedicled left internal mammary artery (LIMA) (n = 95), free LIMA (n = 1), right internal mammary artery (n = 14), radial artery (n = 24), right gastroepiploic artery (n = 5), and saphenous vein grafts (n = 21). Operative mortality was 1.0% (1 of 96). Two patients required reoperation for excessive bleeding. Mean hospital stay was 5.7+/-1.2 days. Overall angiographic patency was 95.0% with LIMA patency of 97.9% (93 of 95). One patient with block in midsegment of LIMA was reoperated using cardiopulmonary bypass. Follow-up ranged from 4 to 17 months (mean 8.2+/-3.1 months). Two patients (one with narrowed LIMA to left anterior descending artery anastomosis, and one with patent anastomosis) had residual angina.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass is a reproducible, effective, and safe option in selected group of patients. A conscientious approach in patient selection and route of operation is required.

Early and follow-up angiography in minimally invasive coronary bypass without mechanical stabilization

BACKGROUND

This study was undertaken to assess the early and late outcome of coronary anastomosis constructed on a beating heart without the help of mechanical stabilization.

METHODS

All consecutive patients (51) from January 1996 to September 1997 who had bypass done by one surgeon using a left minithoracotomy (39) or median sternotomy (12) on a beating heart with occlusive local snares without mechanical stabilization underwent follow-up angiography early (100%) (within 6 hours) and late (63.5%) at a mean of 9.6+/-4.48 months (range, 3.3 to 19.1 months).

RESULTS

The cumulative late patency was 95.4% (83 of 87 patients), with two early and two late occlusions. There was no early or late mortality or perioperative myocardial infarction. Two patients (3.9%) developed recurrent angina. Four anastomotic irregularities (4 of 32 patients, 12.6%) have cleared up on follow-up angiography. There was no evidence of late stenosis at the snare sites used for local occlusion.

CONCLUSIONS

Minimally invasive coronary bypass is safe and effective. Early angiographic abnormalities should be interpreted with caution and we could not demonstrate any long-term deleterious effects of local snaring.

Functional recovery after coronary artery bypass grafting in patients with severe left ventricular dysfunction and preserved myocardial viability in the left anterior descending arterial territory as assessed by thallium-201 myocardial perfusion imaging

To evaluate the functional recovery after coronary bypass surgery in patients with severe left ventricular (LV) dysfunction (ejection fraction (EF) < or = 35%), 100 consecutive patients with viable myocardium in the territory supplied by the left anterior descending artery (LAD) underwent coronary bypass grafting. In addition, cardiac catheterization and single-photon emission computed tomography (SPECT) perfusion imaging with thallium-201 were repeated 1-year postoperatively. Although 12 patients with severe LV dysfunction were preoperatively in a worse New York Heart Association functional class (3.1+/-0.7 vs 2.4+/-0.8; p<0.01), had a higher incidence of heart failure (10/12 vs 14/88; p<0.001) and had a worse LVEF (29+/-5 vs 61+/-14%; p<0.001) compared with 88 patients without severe LV dysfunction, the operative mortality was similar in the 2 groups (1/12 vs 2/88; p=NS). The postoperative NYHA functional class in the patients with severe LV dysfunction was similar to that in the patients without such dysfunction (1.6+/-0.7 vs 1.3+/-0.6; p=NS). In addition, the 1-year postoperative study revealed a significant improvement in the thallium defect score in both the LAD territory (1.7+/-1.2 to 0.7+/-1.0, p=0.01) and all the territories (5.2+/-2.2 to 3.2+/-1.9, p=0.002) in patients with severe LV dysfunction, whereas no improvement in defect score was found in either of these territories in those without severe LV dysfunction (LAD: 0.6+/-1.4 to 0.4+/-1.2, p=NS; All: 1.9+/-2.2 to 1.8+/-2.0, p=NS). Furthermore, a marked 1-year postoperative improvement (15-24%; 95% confidence interval) in LVEF (29+/-5 to 48+/-10%, p<0.001) was demonstrated in patients with severe LV dysfunction, but not in those without such dysfunction (60+/-13 to 61+/-11%, p=NS). These results indicate that myocardial viability in the LAD territory, as demonstrated by thallium-201 SPECT perfusion imaging, predicts a significant improvement in functional class and LVEF of at least 10% or more after coronary artery bypass grafting in patients with severe LV dysfunction.

Rationale and Surgical Techniques for Emerging Procedures in Cardiac Surgery

New techniques continue to emerge in cardiac surgery. This article reviews the history, rationale, techniques, and controversies regarding a variety of novel ap proaches to minimally invasive chest surgery. The suc cess of video-assisted thoracoscopy heralded the mod ern era of these techniques and also serves to illustrate its limitations. Minimally invasive cardiac procedures are outlined with a discussion of the benefits and risks, as well as the media and marketing pressures on surgeons. In addition, robot-assisted surgery and future trends are presented.

Ministernotomy versus median sternotomy for aortic valve replacement: a prospective, randomized study

BACKGROUND

Minimally invasive aortic valve replacement reduces surgical trauma and, supposedly, postoperative pain, blood loss, and length of stay. A prospective, randomized study was designed to prove these theoretical advantages.

METHODS

Forty patients undergoing isolated, elective aortic valve replacement were randomized into two equal groups. Patients in group M underwent aortic valve replacement through a ministernotomy (reversed L or reversed C). In group S, a median sternotomy was used. The anesthetic and surgical protocol was identical for both groups. Pain was evaluated on a daily basis. Pulmonary function tests were performed preoperatively and before hospital discharge in all patients.

RESULTS

There were two deaths in each group. Cross-clamp time was longer in group M: 70 +/- 19 minutes versus 51 +/- 13 minutes in group S (p = 0.005). There were no statistically significant differences between groups M and S in pump time (95 +/- 20 minutes versus 83 +/- 19 minutes), extubation time (9.9 hours in both groups), chest drainage (479 +/- 274 mL/L 24 hours versus 355 +/- 159 mL/24 hours), transfusion requirements (27% in both groups), pain evaluation (1.34 +/- 1.3 versus 2.15 +/- 1.5), length of stay (6.2 +/- 2.3 days versus 6.3 +/- 2.5 days), and cosmetic appraisal. Forced vital capacity decreased 26% from preoperative reference values in group M and 33% in group S (p = not significant). Forced expiratory volume in 1 second decreased 22% and 35%, respectively (p = not significant).

CONCLUSIONS

This study has failed to prove the theoretical advantages of minimally invasive aortic valve replacement. With this technique, cross-clamp time is longer than with a median sternotomy.

Ultra-fast track hospital discharge using conventional cardiac surgical techniques

BACKGROUND

Recent introduction of minimally invasive adult cardiac surgical techniques has emphasized the advantage of early hospital discharge. However, we chose an alternative approach to determine the safety, efficacy, and feasibility of ultra-fast track protocols while retaining both standard surgical exposure (median sternotomy) and conventional cardiac surgical techniques (hypothermia, cardiopulmonary bypass with cardiac arrest, and optimal myocardial protection).

METHODS

From September 1995 to January 1998, a total of 258 consecutive patients underwent cardiac procedures by a single surgeon. Acceleration of clinical pathways was used to initiate earlier discharges. Stringent postdischarge follow-up was implemented. Prospectively entered data were then analyzed retrospectively.

RESULTS

A variety of isolated as well as combined coronary and valve procedures were performed. Of the 258 patients operated on during this entire study period, a total of 144 patients (56%) were discharged within postoperative days 1 to 4 (ultra-fast track discharge). Over the past 12 months, this incidence increased to 70% (76 of 108 patients). Approximately 50% of these patients were operated on urgently or emergently. To date, there have been no deaths in this ultra-fast track group. There were eight brief readmissions, of which one was for rewiring of a noninfected sternal dehiscence, and the remaining were for cardiac diagnostic studies or a noncardiac problem altogether.

CONCLUSIONS

Conventional cardiac operation can allow ultrafast hospital discharges while retaining the advantage of time-tested techniques and providing wider application without requiring new or additional training or equipment.

Minimally invasive direct coronary artery bypass grafting: two-year clinical experience

BACKGROUND

Interest in minimally invasive coronary artery bypass grafting has been increasing.

METHODS

From April 1994 through December 1996, 199 patients (age, 36 to 93 years) underwent minimally invasive coronary artery bypass grafting through minithoracotomy, subxiphoid, and lateral thoracotomy incisions, with internal mammary artery, gastroepiploic artery, and composite grafts placed using local coronary artery occlusion.

RESULTS

The conversion rate to sternotomy was 7% (14/199). Preoperative risk factors included unstable angina (n = 83), reoperative coronary artery bypass grafting (n = 54), low ejection fraction (n = 53), congestive heart failure (n = 44), renal insufficiency (n = 25), chronic obstructive pulmonary disease (n = 36), cerebrovascular accident (n = 22), and diffuse vascular disease (n = 47). Morbidity included wound infections (n = 5), reoperation for management of bleeding (n = 6) and acute graft occlusion (n = 2), perioperative stroke (n = 1), atrial fibrillation (n = 14), and perioperative myocardial infarction (n = 7). The operative mortality was 3.8% (7/185). The number of grafts placed in 185 patients was as follows: single, 156; double, 28; and triple, 1. Early (less than 36 hours) angiography and Doppler flow assessment of the coronary anastomoses in 85% of the patients showed that 92% were patent. Routine use of mechanical stabilization of the coronary artery since April 1996 was found to be associated with an increase in the patency rate of the left internal mammary artery-left anterior descending coronary artery anastomosis to 97%, versus 89% (p = 0.055) associated with conventional immobilization techniques. Of the 148 patients followed up beyond 1 month (range, 1 to 32 months; mean, 9.2 +/- 7.4 months) postoperatively, 3 have died (3 to 7 months), and of the 145 survivors the cardiac-related event (percutaneous transluminal coronary angioplasty, reoperation, readmission for recurrent angina, and congestive heart failure)-free interval was 93%.

CONCLUSIONS

The minimally invasive coronary artery bypass grafting operation is safe and effective. Regional cardiac wall mechanical immobilization enhances the early graft patency and must be considered an essential part of this operation.

[Minimally invasive aortic valve replacement]

INTRODUCTION

Minimally invasive surgery is being applied to certain procedures in cardiac surgery. Aortic valve replacement presents the highest number of cases in which this approach is feasible.

MATERIAL AND METHODS

Fifteen patients, aged 16 to 75 years, underwent aortic valve replacement through a 10 cm incision at the level of the second intercostal space. Cardiopulmonary bypass was instituted through cannulation of the aorta and the femoral vein.

RESULTS

Adequate exposure of the aortic root was achieved in all cases. Valve replacement was accomplished with a mean ischemic time of 50 +/- 6 minutes and a pump time of 80 +/- 14 minutes. Mean chest drainage was of 310 +/- 251 ml. The patients were discharged between the third and the fifth day of the postoperative course.

CONCLUSIONS

A transverse incision at the level of the second intercostal space provides an excellent exposure for aortic valve replacement. Surgical times are not excessively prolonged and patient's recovery is faster and less painful than with the standard midline sternotomy.

Minimally invasive coronary artery bypass: a series with early qualitative angiographic follow-up

BACKGROUND

Notwithstanding the advantages offered by minimally invasive coronary bypass, valid concerns have been raised about the technical accuracy of the distal anastomoses that can be fashioned on a beating heart. The main objective of our study was to undertake early and complete qualitative angiographic graft analysis in all patients undergoing this procedure.

METHODS

All enrolled patients (25) from January to October 1996 who had bypass done by one surgeon via left minithoracotomy (19) or median sternotomy (6) on a beating heart underwent postoperative angiography within 4 to 6 hours. These angiograms were then reviewed for qualitative analysis and compared with a similar series done under conventional cardioplegic arrest.

RESULTS

There was 97.5% graft patency (28/29) and no anastomotic occlusions. One internal thoracic artery was damaged. There was no mortality and no perioperative myocardial infarctions. All patients are alive and symptom free. The follow-up is 100% complete and ranges from 15 days to 11 months. Of the 26 anastomoses that could be assessed, 21 (81%) were grade A and 5 (19%) were grade B. In comparison, 24/25 (96%) of the anastomoses fashioned on an arrested heart by the same surgeon were grade A (p = 0.175).

CONCLUSIONS

Minimally invasive coronary bypass can be carried out effectively and safely in a select group of patients, and the development of stabilizing devices and proper instrumentation should further improve results.

Transient ventricular asystole using adenosine during minimally invasive and open sternotomy coronary artery bypass grafting

BACKGROUND

The emergence of minimally invasive coronary artery bypass grafting and recent off-pump open sternotomy clinical reports have refocused attention on the technical aspects and outcome of grafting on the beating heart.

METHODS

To optimize the surgical field we report a method using adenosine for induction of controlled intervals of ventricular asystole to produce a transiently still cardiac field that facilitates anastomotic accuracy.

RESULTS

Adenosine was used in 57 patients, 31 included off-pump coronary artery bypass grafting (27 by minimally invasive technique, 4 by open sternotomy). In a further 26 patients adenosine pauses were used for suture placement to control anastomotic bleeding after cardiopulmonary bypass. Average adenosine boluses per anastomosis were 9 (6-14), mean dose of adenosine per bolus (mg/kg) was 0.24 (0.15-0.35), mean duration of pause (seconds) was 6 (3-19), and mean time for arterial blood pressure (mean) to return to baseline (seconds) was 35 (13-48). Presence of repolarization arrhythmias was noted in 1 patient. There were no deaths. Two patients had recurrent myocardial ischemia shown on angiography to be the result of technical problems.

CONCLUSIONS

This report describes our experience with the emerging procedure of minimally invasive coronary operations and off-pump grafting with the adenosine technique. The method also includes mechanical devices and other pharmacological therapy to optimize the surgical field, and the technique has now become a standard component of our off-pump revascularization methods.

Less invasive arterial CABG on a beating heart

BACKGROUND

Competitive status of percutaneous transluminal coronary angioplasty and stenting has stimulated an interest in minimally invasive direct coronary artery bypass grafting.

METHODS

Between April 1994 and September 1996,156 patients with a mean age of 67 +/- 10 years have undergone minimally invasive direct coronary artery bypass grafting via minithoracotomy, subxiphoid incision, or both with internal mammary artery, right gastroepiploic artery, and radial artery grafting using local coronary occlusion on a beating heart with immobilization of the coronary artery target sites with traction sutures and mechanical regional cardiac wall immobilization platform.

RESULTS

Morbidity included wound infection (3), reoperation for bleeding (5), atrial fibrillation (12), central nervous system complication (1), and perioperative myocardial infarction (5). Cardiac-related operative mortality was 1.2% (2/156). Predominantly single grafting was done in 128 patients. Routine angiographic and Doppler echocardiographic flow assessment of anastomotic patency showed an overall patency rate of 92%. In 52 recent consecutive patients in whom the regional cardiac wall mechanical stabilization platform was used, the patency rate of the left internal mammary artery-to-left anterior descending coronary artery graft was improved to 96.2%. With a mean followup of 9.2 +/- 7.4 months, cardiac event-free interval (percutaneous transluminal coronary angioplasty, reoperative coronary artery bypass grafting, or death) in 111 patients was 91%.

CONCLUSIONS

Minimally invasive direct coronary artery bypass grafting is safe and effective with good early and midterm clinical results, especially with left internal mammary artery-to-left anterior descending coronary artery grafting via minithoracotomy. Regional cardiac wall immobilization of coronary artery target sites enhances the early graft patency in a predictable manner (96.2%), and this method should be an essential part of all minimally invasive direct coronary artery bypass graft operations with left internal mammary artery-to-left anterior descending artery grafts via minithoracotomy. Further study is required to establish the long-term efficacy of minimally invasive direct coronary artery bypass grafting and the treatment of coronary artery disease.

Minimal access surgery

Images

"Keyhole" coronary artery bypass surgery

OBJECTIVE

The objective of this study was to identify the utility of "keyhole" thoracotomy approaches to single vessel coronary artery bypass surgery.

SUMMARY BACKGROUND DATA

Although minimally invasive surgery is efficacious in a wide variety of surgical disciplines, it has been slow to emerge in cardiac surgery. Among 49 selected patients, the authors have used a left anterior keyhole thoracotomy (6 cm in length) combined with complete dissection of the eternal mammary artery (IMA) pedicle under thoracoscopic guidance or directly through the keyhole incision to accomplish IMA coronary artery bypass grafting (CABG) to the left anterior descending (LAD) coronary artery circulation or to the right coronary artery (RCA).

METHODS

Keyhole CABG was accomplished in 46 of 49 patients in which this approach was attempted. All patients had significant (> 70%) obstruction of a dominant coronary artery that had failed or that was inappropriate for endovascular catheter treatment (percutaneous transluminal coronary angioplasty or stenting). Forty-four of the 49 patients had proximal LAD and 5 had proximal RCA stenoses. The mean age of the patients (35 men and 14 women) was 61 years, and their median New York Heart Association anginal class was III. The mean left ventricular ejection fraction was 42%. Femoral cardiopulmonary bypass support was used in 9 (19%) of 46 patients successfully managed with the keyhole procedure. Short-acting beta-blockade was used in the majority of patients (38 of 46) to reduce heart rate and the vigor of cardiac contraction.

RESULTS

As 49 patients have survived operation, which averaged 248 minutes in duration. Median, postoperative endotracheal intubation time for keyhole patients was 6 hours with 25 of 46 patients being extubated before leaving the operating room. The median hospital stay was 4.3 days. Conversion to sternotomy was required in three patients to accomplish bypass because of inadequate internal mammary conduits or acute cardiovascular decompensation during an attempted off-bypass keyhole procedure Postoperative complications were limited to respiratory difficulty in three patients and the development of a deep wound infection in one patient. Nine (19%) of 46 patients received postoperative transfusion. There have been no intraoperative or postoperative infarctions, and angina has been controlled in all but one patient who subsequently had an IMA-RCA anastomotic stenosis managed successfully with percutaneous transluminal coronary angioplasty.

CONCLUSIONS

These early results with keyhole CABG are encouraging. As experience broadens, keyhole CABG may become a reasonable alternative to repeated endovascular interventions or sternotomy approaches to recalcitrant single-vessel coronary arterial disease involving the proximal LAD or RCA.