Robotic-assisted instruments enhance minimally invasive mitral valve surgery.

BACKGROUND: The potential for totally endoscopic mitral valve surgery has been advanced by the development of minimally invasive techniques. Recently surgical robots have offered instrument access through small ports, obviating the need for a significant thoracotomy. This study tested the hypothesis that a microsurgical robot with 5 degrees of freedom is capable of performing an endoscopic mitral valve replacement (MVR). METHODS: Dogs (n = 6) were placed on peripheral cardiopulmonary bypass; aortic occlusion was achieved with endoaortic clamping and transesophageal echocardiographic control. A small left seventh interspace "service entrance" incision was used to insert sutures, retractor blade, and valve prosthesis. Robotically controlled instruments included a thoracoscope and 5-mm needle holders. MVR was performed using an interrupted suture technique. RESULTS: Excellent visualization was achieved with the thoracoscope. Instrument setup required 25.8 minutes (range 12 to 37); valve replacement required 69.3+/-5.39 minutes (range 48 to 78). MVR was accomplished with normal prosthetic valve function and without misplaced sutures or inadvertent injuries. CONCLUSIONS: This study demonstrates the feasibility of adjunctive use of robotic instrumentation for minimally invasive MVR. Clinical trials are indicated.

Minimally invasive port access surgery reduces operative morbidity for valve replacement in the elderly.

BACKGROUND: Although minimally invasive techniques for valvular surgery have rapidly come into widespread use, whether such an approach can be safely applied to elderly patients remains an open question. To help resolve this issue, we reviewed our experience with minimally invasive port access (MIPA) valve surgery in elderly patients and compared it to the results obtained with the standard sternotomy (STD) approach in the same age group. METHODS: From January 1994 through December 1998, 370 consecutive patients at least 70 years of age underwent isolated aortic or mitral valve surgery at our institution. The standard sternotomy operative approach was used in 259 patients (mean age 77.5 years) and the minimally invasive port access approach was used in 111 patients (mean age 76.0; p=.006). A mitral valve procedure was performed more often in the MIPA patients than in the STD patients (49.5% vs. 35.9%; p < .001). RESULTS: Hospital mortality was comparable in the two groups, 9.7% (25/259) in the STD group and 7.2% (8/111) in the MIPA group (p = .50), as was the incidence of many perioperative complications. The MIPA group, however, had a significantly lower incidence of sepsis or wound complications (1.8% vs 7.7%; p = .027), required less fresh frozen plasma transfusion (median 1.0 unit vs 2.0 units; p =.04), and had a shorter length of hospital stay (11.6 days vs 17.6 days; p = .001). CONCLUSIONS: These results indicate that with appropriate surgical techniques the MIPA approach for isolated valve surgery can be safely applied to the elderly patient population with excellent results. In our initial experience the MIPA approach is associated with significantly less plasma transfusion, fewer postoperative complications, and shorter length of hospital stay.

Choice of mitral prosthesis in the elderly. An analysis of actual outcome.

BACKGROUND: In younger patients requiring mitral valve replacement (MVR), mechanical prostheses (MPs) have been reported to give better freedom from all valve-related complications (VRCs) because of the high incidence of late valve degeneration (VD) associated with bioprostheses (BPs). In older patients, however, the risk of VD may be reduced because of the large competing risk of noncardiac death (NCD). Previous studies on VD in the elderly have used actuarial analysis, which overestimates the risk of VD in this population because it assumes that dead patients are still at risk. In contrast, cumulative incidence (actual) analysis acknowledges that patients who die have no risk of VD. This study compares the results of both "actual" and "actuarial" analyses of the freedom from VD in elderly patients undergoing MVR. METHODS AND RESULTS: From June 1976 through January 1996, 504 patients > or = 70 years of age underwent MVR at our institution. Isolated mitral operations were performed in 159 patients, and 169 had concomitant CABG. Hospital mortality was 59 of 374 (15.9%) for tissue prosthesis versus 24 of 130 (18.5%) for mechanical prosthesis (P = NS). For tissue versus mechanical prosthesis, 10-year freedom from noncardiac death was 75.0% versus 67.6% (P = NS); 10-year actuarial freedom from valve degeneration was 79.8% versus 93.4% (P = NS); 10-year actual freedom from valve degeneration was 92.6% versus 95.4% (P = NS); and 10-year actual freedom from all VRCs was 84.4% versus 92.3% (P = NS). CONCLUSIONS: In elderly patients undergoing MVR, actuarial analysis overestimates the 10-year risk of VD compared with actual analysis (20.2% versus 7.4% for BP, 6.6% versus 4.6% for MP). In these patients, the actual freedoms from VD and all VRCs do not differ significantly between BP and MP. Thus, in this age group, the necessity for anticoagulation or its avoidance may be the predominant factor in choosing a replacement mitral valve.

Minimally invasive port-access coronary artery bypass grafting with early angiographic follow-up: initial clinical experience.

OBJECTIVE: New techniques for minimally invasive coronary artery bypass grafting have recently emerged. The purpose of this study was to determine the safety and efficacy of Port-Access (Heartport, Inc., Redwood City, Calif.) coronary revascularization and to evaluate with angiography the early graft patency rate with this new approach. METHODS: From October 1996 to May 1997, 31 patients underwent Port-Access coronary artery bypass grafting with an anterior minithoracotomy and endovascular-occlusion cardiopulmonary bypass. There were 26 men and 5 women with a mean age of 62 years (range 42 to 82 years). Fifteen patients underwent single bypass; 12 patients underwent double bypass, and 4 patients underwent triple bypass. Bypass conduits included the left internal thoracic artery (n = 30), right internal thoracic artery (n = 2), radial artery (n = 10), and saphenous vein (n = 6). Three sequential grafts were used. Angiographic studies of the bypass grafts were performed in 27 of 31 patients (87%). RESULTS: There were no deaths, neurologic deficits, myocardial infarctions, or aortic dissections. Conversion to sternotomy was not required in any case. There were two reoperations for bleeding, one reoperation for tamponade, and one reoperation for pulmonary embolus. Postoperative angiography revealed anastomotic patency of the left internal thoracic artery to left anterior descending artery in 26 of 26 grafts (100%) with overall anastomotic patency in 43 of 44 grafts (97.7%). CONCLUSION: These results demonstrate that Port-Access coronary artery bypass can be performed accurately and safely with acceptable morbidity. This approach allows for multivessel revascularization on an arrested, protected heart with excellent anastomotic precision and reproducible early graft patency.

Valve repair versus replacement for mitral insufficiency: when is a mechanical valve still indicated?

OBJECTIVES: Although many advantages of mitral valve reconstruction have been demonstrated, whether specific subgroups of patients exist in whom mechanical valve replacement offers advantages over mitral reconstruction remains undetermined. METHODS: This study examined the late results of mitral valve surgery in patients with mitral insufficiency who received either a St. Jude Medical valve (n = 514) or a mitral valve reconstruction with ring annuloplasty (n = 725) between 1980 and 1996. RESULTS: Overall operative mortality was 7.2% in the patients receiving a St. Jude Medical mitral valve and 5.4% in those undergoing mitral valve reconstruction (no significant difference); isolated mortality was 2.5% in the St. Jude Medical group and 2.2% in the valve reconstruction group (no significant difference). The follow-up interval was more than 5 years for 340 patients with a mean of 39.8 months (98.5% complete). Overall 8-year freedom from late cardiac death, reoperation, and all valve-related complications was 72.8% for the St. Jude Medical group and 64.8% for valve reconstruction group (no significant difference). For patients with isolated, nonrheumatic mitral valve disease, 8-year freedom from late cardiac death and reoperation was better in the mitral valve reconstruction group (88.3%) than in the St. Jude Medical valve group (86.0%; p = 0.05). Furthermore, Cox proportional hazards regression revealed that mitral valve reconstruction was independently associated with a lesser incidence of late cardiac death (p = 0.04), irrespective of preoperative New York Heart Association class. However, the St. Jude Medical valve offered better 8-year freedom from late cardiac death, reoperation, and all valve-related complications than did mitral valve reconstruction in patients with multiple valve disease (77.0% vs 45.3%; p < 0.01). CONCLUSIONS: Therefore, mitral valve reconstruction appears to be the procedure of choice for isolated, nonrheumatic disease, whereas insertion of a St. Jude Medical valve should be preferred for patients with multiple valve disease.

Port-Access mitral valve surgery: summary of results.

BACKGROUND: The purpose of this study was to review the short-term results of an initial experience with minimally invasive cardiac valve surgery using the Port-Access approach in terms of feasibility, safety, and reproducibility. METHODS: Between October 1995 and October 1997, 151 minimally invasive cardiac valve procedures were performed at our institution using the Port-Access approach. The patients' mean age was 58.1 years (range 21 to 91 years) and 50% were male. Aortic valve replacement was performed in 35 (23.2%) patients, mitral valve repair in 56 (37.1%) patients, mitral valve replacement in 36 (23.8%) patients, and complex valve procedures in 24 (15.9%) patients. RESULTS: The operative mortality rate for isolated mitral valve surgery was 1.1% (1/92) and for all mitral valve surgery 3.5% (4/113). The operative mortality rate for isolated aortic valve patients was 5.7% (2/35). For the total group the operating mortality was 4% (6/151). Early complications for mitral valve patients included reoperation for bleeding or tamponade in 5 (4.4%) patients, myocardial infarction in 2 (1.2%) patients, and transient ischemic attack and wound infection in 1 (0.1%) patient each. One patient required reoperation for mitral valve failure that resulted in aortic dissection unrelated to the Endoaortic Clamp catheter and ultimately led to death. Two (5.6%) aortic valve patients required reoperation for bleeding and two (5.6%) required reoperation for tamponade. CONCLUSIONS: Minimally invasive Port-Access techniques can be applied to most patients with valvular heart disease with minimal morbidity and mortality and good postoperative valve function and may be the preferred approach for isolated mitral and aortic valve surgery.

Single and multivessel port-access coronary artery bypass grafting with cardioplegic arrest: technique and reproducibility.

OBJECTIVES: Although minimally invasive coronary artery bypass grafting is now feasible, using this technique to perform anastomoses on the beating or fibrillating heart may yield poorer graft patency than the standard open techniques that use cardioplegic arrest. This study tested the feasibility and anastomotic reproducibility of minimally invasive coronary bypass using newly developed port-access coronary artery bypass technology (Heartport, Inc., Redwood City, Calif.), which allows endovascular cardiopulmonary bypass, cardiac venting, aortic occlusion, and cardioplegic arrest for internal thoracic artery-coronary artery anastomoses. METHODS: Nineteen dogs had thoracoscopic takedown of either single (n = 14) or bilateral (n = 5) internal thoracic arteries followed by minimally invasive coronary bypass with cardioplegic arrest, done by means of the port-access system. The anastomotic technique was modified after the fourth animal by switching from a microscope to a 2.5 cm oval port and performing a conventional anastomosis with operative loupes. The adequacy of delivery of cardioplegic solution, ventricular decompression, and anastomotic patency was assessed. RESULTS: The crossclamp and bypass times were 50 +/- 15 minutes and 87 +/- 28 minutes (mean +/- standard deviation), respectively. The mean myocardial temperature after cardioplegia was 17 degrees +/- 1 degree C and the aortic pressure (-3 +/- 9 mm Hg) and pulmonary artery pressure (4 +/- 1 mm Hg) were low throughout the procedure. All animals were weaned from bypass without inotropic agents. Angiograms and autopsies demonstrated successful thoracic artery takedown and anastomotic patency in 18 of 19 animals, with 100% anastomotic patency after the technique had been modified after the fourth animal. CONCLUSION: This study describes a reproducible technique for minimally invasive coronary bypass that allows myocardial protection, anastomotic precision, and predictable thoracic artery graft patency. Clinical trials are indicated.

Minimally invasive mitral valve replacement: port-access technique, feasibility, and myocardial functional preservation.

OBJECTIVE: This experiment examined the feasibility of minimally invasive port-access mitral valve replacement via a 2.5 cm incision. METHODS: The study evaluated valvular performance and myocardial functional recovery in six mongrel dogs after port-access mitral valve replacement with a St. Jude Medical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). Femoro-femoral cardiopulmonary bypass and a balloon catheter system for myocardial protection with cardioplegic arrest (Heartport, Inc., Redwood City, Calif.) were used. The mitral valve was replaced through a 2.5 cm port in the left side of the chest, and the animals were weaned from bypass. Cardiac function was measured before and at 30 and 60 minutes after bypass. Left ventricular pressure and electrical conductance volume were used to calculate changes in load-independent indexes of ventricular function. RESULTS: Each procedure was successfully completed. Recovery of left ventricular function was excellent at 30 and 60 minutes after bypass compared with the prebypass values for elastance (30 minutes = 4.04 +/- 0.97 and 60 minutes = 4.27 +/- 0.57 vs prebypass = 4.45 +/- 0.96; p = 0.51) and for preload recruitable stroke work (30 minutes = 76.23 +/- 4.80 and 60 minutes = 71.21 +/- 2.99 vs prebypass = 71.23 +/- 3.75; p = 0.45). Preload recruitable work area remained at 96% and 85% of baseline at 30 and 60 minutes (p = not significant). In addition, transesophageal echocardiography demonstrated normal prosthetic valve function, as well as normal regional and global ventricular wall motion. Autopsy revealed secure annular-sewing apposition and normal leaflet motion. CONCLUSIONS: These results suggest that minimally invasive mitral valve replacement using percutaneous cardiopulmonary bypass with cardioplegic arrest is technically reproducible, achieves normal valve placement, and results in complete cardiac functional recovery. Minimally invasive mitral valve replacement is now feasible, and clinical trials are indicated.