Comparative differences of mitral valve-in-valve implantation: A new mitral bioprosthesis versus current mosaic and epic valves.

OBJECTIVE: Evaluate transcatheter mitral valve replacement (TMVR) valve-in-valve (VIV) outcomes in three different mitral bioprostheses (of comparable measured internal diameters) under stable hemodynamic and surgical conditions by bench, echocardiographic, computerized tomography (CT), and autopsy comparisons pre- and post-valve implantation in a porcine model under matched controlled conditions. BACKGROUND: Impact of surgical bioprosthesis design on TMVR VIV procedures is unknown. METHODS: Fifteen similar-sized Yorkshire pigs underwent pre-procedural CT screening. Twelve had consistent anatomic features and underwent implantation of mitral bioprostheses. Four valves from each of three manufacturers were implanted in randomized fashion: 27-mm Epic, 27-mm Mosaic, and 25-mm Mitris, followed by TMVR VIV with 26 Edwards Sapien3. Post-VIV, suprasternal TEE studies were performed to assess hemodynamic function, followed by a gated contrast CT. After euthanasia, animals underwent necropsy for anatomic evaluation. RESULTS: All 12 animals had successful VIV implantation with no study deaths. The post vivMitris (3.77 ± 0.36)/(2.2 ± 0.25 mmHg) had the lowest peak/mean trans-mitral gradient and the vivEpic the highest (15.5 ± 2.55)/(7.09 ± 1.13 mmHg). All THVs (transcatheter heart valves) had greatest deformation within the center of the THV frame; with the smallest waist opening area in the vivEpic (329 ± 35.8 mm2 ) and greatest in the vivMitris (414 ± 33.12 mm2 ). Bioprosthetic frames without obvious radiopaque markers resulted in the most ventricular implantation of the THV's anteroseptal frame (Epic: -4.52 ± 0.76 mm), versus the most radiopaque bioprosthesis (Mitris: -1.18 ± 2.95 mm), and higher peak LVOT gradients (Epic: 4.82 ± 1.61 mmHg; Mitris: 2.91 ± 1.47 mmHg). CONCLUSIONS: The current study demonstrates marked variations in hemodynamics, THV opening area, and anatomic dimensions among measured similarly sized mitral bioprostheses. These data suggest a critical need for understanding the potential impact of variations in bioprosthesis design on TMVR VIV clinical outcomes.

Comparison of a new bioprosthetic mitral valve to other commercially available devices under controlled conditions in a porcine model.

BACKGROUND/AIM: To evaluate three mitral bioprostheses (of comparable measured internal diameters) under controlled, stable, hemodynamic and surgical conditions by bench, echocardiographic, computerized tomography and autopsy comparisons pre- and postvalve implantation. METHODS: Fifteen similar-sized Yorkshire pigs underwent preprocedural computerized tomography anatomic screening. Of these, 12 had consistent anatomic features and underwent implantation of a mitral bioprosthesis via thoracotomy on cardiopulmonary bypass (CPB). Four valves from each of three manufacturers were implanted in randomized fashion: 27-mm Epic, 27-mm Mosaic, and 25-mm Mitris bioprostheses. After CPB, epicardial echocardiographic studies were performed to assess hemodynamic function and define any paravalvular leaks, followed by postoperative gated contrast computerized tomography. After euthanasia, animals underwent necropsy for anatomic evaluation. RESULTS: All 12 animals had successful valve implantation with no study deaths. Postoperative echocardiographic trans-valve gradients varied among bioprosthesis manufacturers. The 25-mm Mitris (5.1 ± 2.7)/(2.6 ± 1.3 torr) had the lowest peak/mean gradient and the 27-mm Epic bioprosthesis had the highest (9.2 ± 3.7)/(4.6 ± 1.9 torr). Surgical valve opening area (SOA) varied with the 25-mm Mitris having the largest SOA (2.4 ± 0.15 cm2 ) followed by the 27-mm Mosaic (2.04 ± 0.23 cm2 ) and the 27-mm Epic (1.8 ± 0.27 cm2 ) valve. Bench device orthogonal internal diameter measurements did not match manufacturer device size labeling: 25-mm Mitris (23 × 23 mm), 27-mm Mosaic (23 × 22 mm), 27-mm Epic (21 × 21 mm). CONCLUSIONS: Current advertisement/packaging of commercial surgical mitral valves is not uniform. This study demonstrates marked variations in hemodynamics, valve opening area and anatomic dimensions between similar sized mitral bioprostheses. These data suggest a critical need for standardization and close scientific evaluation of surgical mitral bioprostheses to ensure optimal clinical outcomes.

Biomedical innovation: a risky business at risk.

Regulatory and financial challenges conspire to stall the development and market approval of breakthrough medical products. Inconsistent parameters are used to assess the safety and efficacy of drugs, biologics, and devices; this glitch in the system introduces uncertainty, slows or blocks product approvals, and increases the costs of product development. Here, we consider how to balance the benefits and risks to the public in the assessment of innovative medical products. We also discuss the Institute of Medicine's recent report on the medical device approval process.

Deployment and operation of a transportable burn intensive care unit in response to a burn multiple casualty incident.

In many hospitals, intensive care units (ICUs) operate at or above capacity on a daily basis. Multiple casualty incidents will create a sudden need for additional ICU beds and hospital planning for disaster response must anticipate the need for rapid ICU expansion. In this article, the authors describe the management of 6 patients who were burned in Guam and successfully transported a distance of 7,268 miles to San Antonio, TX, for tertiary burn center care. The mission required creation of a temporary burn ICU at Tripler Army Medical Center in Hawaii, approximately midway between the referring hospital and the receiving burn center. A method of creating a temporary burn center is described. Lessons learned, including the need to standardize equipment, and to cross-train and cross-credential medical personnel, are applicable to both military and civilian mass casualty management.

Use of step-section histopathology to evaluate 18F-fluorocholine PET sextant localization of prostate cancer.

To assess positron emission tomography (PET) with fluorine-18 fluorocholine for sextant localization of malignant prostate tumors. Histopathologic analysis was performed on step-sectioned whole-mounted prostate specimens from 15 patients who underwent PET with fluorocholine prior to radical prostatectomy. The maximum standardized uptake value (SUVmax) corresponding to prostate sextants on PET was measured by region of interest analysis and compared with histopathologic results. Histopathology demonstrated malignant involvement in 61 of 90 prostate sextants. The mean total tumor volume per specimen was 4.9 mL (range 0.01-28.7 mL). Mean SUVmax was 6.0+/-2.0 in malignant sextants and 3.8+/-1.4 in benign sextants (p<.0001). The area under the receiver operating characteristic curve was 0.82 for sextant detection of malignancy based on SUVmax measurement. Tumor diameter directly correlated with sextant SUVmax in malignant sextants (r=.54, p<.05). In 13 subjects, the largest tumor in the specimen corresponded to the sextant with the highest SUVmax. Fluorocholine PET can serve to localize dominant areas of malignancy in patients with prostate cancer. However, PET with fluorocholine may fail to identify sextants with smaller volumes of malignancy.

Case report: Endoscopic laser lithotripsy of seminal-vesicle stones.

A 25-year-old man presented with painful ejaculation, an ejaculate volume of 0.75, and complaints of passing "granules" in the semen. Transrectal ultrasonography showed bilateral seminal vesicle enlargement. The patient underwent transurethral resection of the ejaculatory duct. The entry point of duct was resected using pure cutting current, resulting in the passage of multiple proteinaceous-appearing stones. Approximately 10 months later, the patient reported recurrent painful ejaculation and passage of granules in his semen. At cystoscopy, the ejaculatory duct openings were intubated with a cone-tipped catheter to perform bilateral seminal vesiculograms, which showed numerous mobile filling defects and a Steinstrasse appearance at the ejaculatory ducts. A 7F semirigid ureteroscope entered the lumen without difficulty over a guidewire, and the stones were fragmented with a 270-microm holmium laser fiber. The ejaculatory ducts were balloon dilated to 18F. To our knowledge, this is the first reported case where a ureteroscope was utilized to treat seminal-vesicle stones. The seminal vesiculogram proved to be extremely valuable in the diagnosis.

Relationship between activated clotting time during percutaneous intervention and subsequent bleeding complications.

BACKGROUND: Approximately 50% of percutaneous coronary interventions in the United States are performed with unfractionated heparin and no IIb/IIIa agent. The operator must weigh the risks and benefits of more intensive anticoagulation during these percutaneous interventions. This study helps clarify the relationship between patient and procedural factors, such as the intensity of heparin anticoagulation as measured by activated clotting time (ACT), and the risk of blood loss and bleeding complications. METHODS: Four hundred twenty-nine patients undergoing elective or urgent percutaneous coronary intervention were followed up prospectively for 72 hours after intervention for clinical bleeding complications. Blood loss, defined as the difference between preprocedural and nadir postprocedural hematocrit adjusted for interval transfusions, was also tracked. In-laboratory ACTs, as well as other potential clinical and procedural predictors of blood loss and bleeding risk, were collected and analyzed. RESULTS: Maximum in-laboratory ACT was significantly related to blood loss as measured by the change in hematocrit (P =.017) and to the risk of major bleeding complications (P =.002). In multivariate analysis, patient age (P =.004), sex (P =.014), procedure length (P <.001), and additional interventions (P <.001) were significant, independent predictors of blood loss. Major bleeding complications were significantly, independently predicted by patient age (P <.001), additional interventions (P =.015), and maximum in-laboratory ACT (P <.001). CONCLUSIONS: Compared with the other clinical and procedural predictors of bleeding complications, maximum in-laboratory ACT was second only to patient age in significance as a multivariate predictor of postprocedural bleeding complications. Maximum in-laboratory ACT was found to be the most significant modifiable univariate and multivariate predictor of clinical bleeding complications after percutaneous coronary intervention. Particularly in patients with nonmodifiable risk factors for blood loss and bleeding complications such as advanced age, female sex, and multiple and prolonged procedures, avoiding high intensity anticoagulation with unfractionated heparin is associated with lower bleeding risk.