A transatrial pericardial access: lead placement as proof of concept.

A safe, easy, and quick access into the pericardial space may provide a window for diagnostics and therapeutics to the heart. The objective of this study was to provide proof of concept for an engagement and access catheter that allows access to the pericardial space percutaneously. A multilumen catheter was developed to allow navigation and suction fixation to the right atrial appendage/wall in a normal swine model. Advancement through the multilumen catheter using a second catheter with a distal needle tip allows access to the pericardial space without pericardial puncture and advancement of a standard guide wire into the space. Navigation into the pericardial space was undertaken by fluoroscopy alone and was accomplished in 10 swine (5 acute and 5 chronic). As a specific application of this pericardial access method, a pacing lead was implanted on the epicardial surface. Five chronic swine experiments were conducted with successful pacing engagement verified by lead impedance and pacing threshold and sensing. Lead impedance exceeded 1,000 Omega preengagement and dropped by an average of 200 Omega upon implant (769 +/- 498 Omega). Pacing thresholds at 0.4 ms ranged from approximately 0.5 to 2.1 V acutely (1.03 +/- 0.92 V). No cardiac effusion or tamponade was observed in any of the acute or chronic studies. The ability to engage, maintain, and retract the right atrial appendage/wall and to engage an epicardial lead was successfully demonstrated. These findings support the feasibility of safe access into the pericardial space in a normal swine model and warrant further investigations for clinical translation.

Particulate emboli capture by an intra-aortic filter device during cardiac surgery.

OBJECTIVE: Particulate embolization is associated with neurologic morbidity after cardiac surgery. Crossclamp manipulation has been identified as the single most significant cause of particulate emboli release during cardiac surgery. A new intra-aortic filtration method has been assessed with regard to its safety and its ability to capture particulate emboli before they enter the central circulation. METHODS: Patients undergoing cardiac surgery with cardiopulmonary bypass through standard median sternotomy were selected for emboli management by means of intra-aortic filtration. A novel intra-aortic filter device was inserted through a modified 24F arterial cannula immediately before releasing the crossclamp in 77 patients. Filters remained in the aorta until cardiopulmonary bypass was discontinued and the heart was fully ejecting. The procedure was assessed for facility, safety, and effect on routine cardiopulmonary bypass operation and function. RESULTS: The insertion and removal of the intra-aortic filter were safe, easy, and uneventful in most patients. Patient hemodynamics and bypass flow rates remained normal throughout the filter dwell period. No strokes or gross neurologic defects were noted. Electron microscopic analysis of 12 filters revealed an insignificant degree of platelet adhesion on filter surfaces. Histology samples (n = 44) were examined, and 66% (n = 29) showed evidence of atheromatous material, 36% (n = 16) with platelet-fibrin, 25% (n = 11) with true thrombus and/or blood clot, 7% (n = 3) with normal vessel wall, and 2% (n = 1) with aggregates of cholesterol or grumous portion of atheromatous plaque. CONCLUSION: The intra-aortic filter can be safely deployed and captures particulate emboli, the predominant origin of which is atheromatous. The beneficial effects of this device on neurologic outcomes have yet to be determined.

A new method of myocardial revascularization with the radial artery.

We present a new method of myocardial revascularization. The radial artery is used in combination with the left internal mammary artery, thereby providing three distal end-to-side anastomoses to the left anterior descending coronary artery and other sites as determined by the coronary artery lesions. Arterial conduits form an anastomotic network between the left internal mammary artery and the radial artery in a horseshoe pattern. Three coronary arteries are revascularized by two arterial conduits in the left coronary system.

Aortic valve replacement with the Unique Suture Line Stentless USL porcine valve: A new, simple, and safe stentless valve implantation technique.

The Stentless USL, Unique Suture Line porcine valve, is a stentless bioprosthesis developed following the advantages of the studies of the physiology of the aortic root as a functional unit. The direct suturing of the porcine tissue on the soft and elastic tissue of the host's aortic annulus and root gives the bioprosthesis the possibility to follow the physiological movements of the natural valve during the cardiac cycle. For the same reason, there is decreased stress on the valve tissue, especially at the commissural level. There is less technical demand for surgeons who have limited experience with the freehand or miniroot technique due to the limited availability of the homografts because the Stentless USL valve can be implanted with the same technique used with a conventional stented valve. The implant technique used for the Stentless USL valve has advantages, especially in the small aortic calcified annulus in elderly patients where the freehand technique can be difficult and the second suture line can be dangerous (i.e., coronary ostium near the aortic ring or in calcified aortic wall). Our experience with this stentless valve in approximately 200 patients (> 70 years old) shows it to have excellent hemodynamic results even in small valve sizes. The use of this valve and the simple implantation technique avoids the need for complicated aortic root enlargement procedures.

Low profile Liotta bioprosthesis: late follow-up.

A method for supporting the porcine valve was devised to approximate more closely the normal porcine anatomy. This mounting technique resulted in a low profile valve with a greater valve orifice and a lower transvalvular gradient than other porcine bioprostheses (Liotta BioImplant L.P.B., BioImplant, Canada, Inc). There were 297 valves implanted in 279 patients operated on from November 1978 through December 1981. Of these, there were 132 aortic valve replacements (AVR), 129 mitral valve replacements (MVR), and 18 double valve replacements (DVR). The actuarial curve at 72 months showed a late patient survival of 78.48% +/- 5.68% for AVR, 86.27% +/- 4.3% for MVR, and 77.78% +/- 12.2% for DVR. Of these, 93.6% of the AVR patients and 81% of the MVR patients remained in the New York Heart Association Class I postoperatively.

Thromboembolism with low profile bioprosthesis.

Low profile bioprosthesis late follow-up indicates a low incidence of thromboembolism. For the entire series of 415 consecutively operated patients (rigid and flexible stents) the actuarial probability of freedom at 6 years is 90.3% (87.8% for MVR and 92.27% for AVR and 95.24% for MVR + AVR). The linearized incidence for MVR, is 2.5 +/- 0.62 per one hundred patients per year. For AVR this is 1.2 +/- 0.49 per one hundred patients per year. The probability of freedom of thromboembolism of the new flexible stent series (247 patients) at 48 months is 90.92% for MVR, 96.6% for AVR and 100% for MVR + AVR. Endocarditis for the entire series of patients (rigid/flexible stents) at 6 years is low: the linearized incidence for both MVR and AVR is 0.54 per one hundred patients per year. Tissues degeneration, after 5 years follow-up, in patients over 35 years old carrying LPB mounted on flexible stents was not observed. In the series of MVR patients, 17/209 presented thromboembolic complications. In the group of 17 patients, 88% had atrial fibrillation before surgery and 47% of the same group were on warfarin anticoagulation therapy when the embolic accident occurred. The indications for permanent anticoagulation therapy following bioprosthetic MVR in patients with chronic atrial fibrillation is still uncertain.

The low profile bioprosthesis: results with 491 valves implanted in 453 patients for up to 5 years.

This report summarizes results of the first 453 consecutive patients who had 491 low profile bioprostheses implanted at the Italian Hospital in Buenos Aires over a 5-year period. During this time, with the goal of long-term durability, the valve mounting technique was slightly modified, whereas the materials and design of the annulus underwent more extensive changes.