Faculty Bibliography

BACKGROUND: This study reviews the results of an initial experience with minimally invasive coronary bypass surgery using the Port-Access approach in terms of early outcome and safety. METHODS: Between October 1996 and July 1997 49 Port-Access minimally invasive coronary artery bypass grafting procedures were performed at our institution. The patients' mean age was 59.8 years (range 34 to 82 years). Sixteen patients received single vessel and 37 patients received multivessel bypass grafts. RESULTS: There were no operative deaths and no perioperative myocardial infarctions, neurological deficits, or conversions to sternotomy. Early complications included reoperation due to bleeding in 4 patients, reoperation for a pulmonary embolus in 1 patient, and angioplasty for occlusion of a right coronary artery graft in 2 patients. Postoperative angiograms were obtained in 86% (42/49) of the patients and showed 100% patency for left internal mammary artery to left anterior descending artery grafts and 96% patency for all grafts. CONCLUSIONS: These results demonstrate that Port-Access coronary artery bypass grafting using endovascular techniques for cardiopulmonary bypass and cardioplegic arrest can be performed safely with minimal morbidity and mortality. This technique allows multivessel revascularization on a protected, arrested heart with excellent anastomotic precision and reproducible early graft patency. Expanded use of Port-Access techniques is indicated in patients with multivessel coronary artery disease and the technique should be considered for patients with left anterior descending artery restenosis and patients with complex left anterior descending artery lesions where angioplasty results are suboptimal

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

Experiences with 1,000 patients undergoing mitral valve reconstruction at New York University over the past 18 years are summarized. A continuing follow-up (98% complete) demonstrated that 88% of patients are free from recurrent insufficiency 10 years after the operation. Reconstruction is feasible in nearly 90% of patients with mitral valve prolapse, with an operative mortality near 2%. Accordingly, operation is now recommended at an early stage with the first sign of left ventricular systolic dysfunction, while the patient is still in sinus rhythm. Most operations have been done with the Carpentier techniques of segmental resection with annuloplasty and insertion of a Carpentier ring. Recently, two other repair techniques and a minimally invasive operative approach have been evaluated. A triangular resection of a prolapsing anterior leaflet has been done in more than 100 patients with excellent results. Also, a posterior 'folding plasty' has been employed in more than 40 patients with a large redundant posterior leaflet, minimizing the need for annular plication. A minimally invasive approach to the mitral valve has now been employed in 130 patients over the past year, using a right mini-thoracotomy and the Port-Access (Heartport, Inc, Menlo Park, CA) approach. This technique employs catheters introduced through femoral vessels to institute cardiopulmonary bypass and cardioplegic arrest. The operative approach and techniques for mitral valve reconstructive operations continue to evolve, with excellent results and improved patient benefits

Polymorphonuclear leukocyte (PMN) superoxide (.O2-) production has been implicated in the pathogenesis of cardiopulmonary bypass (CPB)-related end organ injury. PMN 'priming' has been described as an event which enhances the release of .O2- following a second, activating insult. We hypothesized that PMN priming occurs during CBP and is temporally related to the plasma level of complement (C3a), interleukin (IL)-6, and IL-8. PMNs were isolated from 10 CPB patients pre-bypass (preCPB), 5 min after protamine administration (PROT), and at 6 and 24 h post-CPB. PMN .O2- production was measured by a cytochrome c reduction assay in the presence or absence of either phorbol 12-myristate-13-acetate (PMA, 0.4 microgram/ml) or N-formyl-methionyl-leucyl-phenylalanine (FMLP, 1 microM) and also after priming with 2000 nM platelet-activating factor (PAF) followed by activation with either PMA or FMLP. Plasma levels of C3a, IL-6, and IL-8 were determined by enzyme-linked immunosorbent assay. PMA-activated PMN .O2- production was significantly elevated at 6 h post-CPB compared to pre-CPB levels (11.04 +/- 0.9 vs 7.62 +/- 0.57, P = 0.009), indicating that CPB is associated with in vivo PMN priming. When PMNs were primed in vitro with PAF and then activated with PMA or FMLP, .O2- release at 6 h post-CPB was also significantly greater than pre-CPB levels (16.04 +/- 0.74 vs 12.2 +/- 0.92, P = 0.038; and 17.33 +/- 1.38 vs 13.33 +/- 1.35, P < 0.05), indicating that CPB acts synergistically with PAF to prime PMNs. Levels of C3a rose significantly over pre-CPB levels at PROT (P = 0.001), and IL-6 and IL-8 rose over pre-CPB levels at 6 h post-CPB (P = 0.01 and P = 0.006, respectively). These findings demonstrate that CPB not only directly primes PMNs, but also potentiates priming of PMNs by PAF. This 'primed' PMN state, which coincided with the increased plasma levels of inflammatory mediators, may suggest a mechanism of predisposition to organ dysfunction following CPB

BACKGROUND: Standard reconstruction for posterior mitral leaflet (PML) disease is quadrangular resection and annular plication; when the PML is excessively high, a sliding plasty is used. We have developed an alternative technique, a posterior leaflet folding plasty. It is performed by folding down the cut vertical edges of the PML. The central height of the PML is reduced, leaflet coaptation is moved posteriorly, and annular plication is unnecessary. METHODS: From March 1995 to August 1996, 26 (17.9%) of 145 patients undergoing mitral reconstruction had a posterior leaflet folding plasty. Concomitant procedures included anterior leaflet resection or resuspension and myotomy and myectomy. In 3 patients, the PML resection extended to a commissure. RESULTS: There was one death and no reoperations. The mean New York Heart Association class was improved from 2.4 preoperatively to 1.4. There was no major postoperative mitral insufficiency in the 26 patients. Systolic anterior motion was transiently seen in 1 patient in whom left ventricular outflow tract obstruction was present preoperatively. CONCLUSIONS: The data demonstrate the safety and short-term efficacy of posterior leaflet folding plasty. This technique may help avoid systolic anterior motion after reconstruction of the PML

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

BACKGROUND: Neointima formation after human saphenous vein grafting (hSVG) involves several matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). This study assessed the feasibility of modulating MMP activity in hSVGs by adenovirus-mediated gene transfer. METHODS: First, 1 x 10(9) plaque-forming units (pfu) of replication-deficient recombinant adenoviruses encoding either beta-galactosidase (ad beta gal), MMP-3 (AdMMP-3), or TIMP-1 (AdTIMP-1) were added into the lumen of hSVGs for 1 hour. After incubation at 37 degrees C for 24 hours, specimens were analyzed by immunohistochemistry, in situ zymography, and X-gal staining. RESULTS: By X-gal staining ad beta gal-infected hSVGs stained positively in the intima and occasionally in the media. Immunohistochemistry of AdMMP-3- and AdTIMP-1-infected hSVGs localized these proteins to the intima. In situ zymography showed increased MMP activity in the intima of AdMMP-3-infected hSVGs relative to AdTIMP-1- or Ad beta gal-infected vessels. CONCLUSIONS: MMP-3 and TIMP activity can be regulated in hSVGs by replication-deficient recombinant adenoviruses. We have previously demonstrated that MMP-3 or TIMP-1 transduction, or both, inhibit SMC migration in an in vitro reconstituted vessel wall. Modulation of MMP activity may thus afford high patency rates in genetically engineered hSVGs. However, adenovirus-mediated gene delivery is limited to the vessel's intima; strategies to infect medial smooth muscle cells need to be developed

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

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

In this study, we sought to determine the use of transesophageal echocardiography (TEE) as the primary imaging technique to assist in the placement of endovascular catheters during minimally invasive, port-access cardiac surgery. The recent development of endovascular catheters that are placed via the femoral artery and vein has enabled patients to be placed on cardiopulmonary bypass without the need for direct visualization of the heart or great vessels via sternotomy. This has allowed cardiac surgery to be performed through smaller thoracotomy incisions. Placement of these catheters has previously been performed with fluoroscopic guidance, which has major imaging limitations. Thirty-six patients underwent port-access cardiac surgery at our institution during the study period. All patients underwent intraoperative TEE. We used TEE to visualize the coronary sinus os, right atrium and superior vena cava, and thoracic aorta to assist with placement of the coronary sinus catheter, venous cannula, and endoaortic clamp. Twenty patients underwent mitral valve surgery, 14 patients coronary artery bypass grafting, 1 patient aortic valve replacement, and 1 patient repair of an atrial septal defect by the port-access approach. TEE was able to adequately visualize the cardiac structures and assist in the placement of the endovascular catheters in all patients. Fluoroscopy was only helpful as an aid to TEE for placement of the coronary sinus catheter. TEE is an excellent imaging modality for the proper placement of these new endovascular catheters, obviating the need for fluoroscopy, except to be on standby and for placement of the coronary sinus catheter