A novel operator-independent noninvasive device for assessing arterial reactivity.

Background: Endothelial dysfunction is associated with increased risk of cardiovascular disease (CVD). Currently available noninvasive methods of measuring endothelial function have limitations. We tested a novel device that provides an automated measurement of the difference between baseline and post-ischemic, hyperemia-induced, brachial arterial compliance, a phenomenon known to be endothelium-dependent. The association between the calculated index, Flow-mediated Compliance Response (FCR), and established CVD risk indices was determined. Methods: Adults with CVD risk factors or known coronary artery disease (CAD) were enrolled. Framingham Risk Score (FRS) was calculated and presence of metabolic syndrome (MetSyn) was assessed. Carotid artery plaques were identified by ultrasound. Cardiorespiratory fitness was assessed by 6-minute walk test (6MWT). FCR was measured using the device. Results: Among 135 participants, mean age 49.3 +/- 17.9 years, characteristics included: 48% female, 7% smokers, 7% CAD, 10% type 2 diabetes, 34% MetSyn, and 38% with carotid plaque. Those with MetSyn had 24% lower FCR than those without (p < 0.001). Lower FCR was associated with higher FRS percentile (r = -0.29, p < 0.001), more MetSyn factors (r = -0.30, p < 0.001), more carotid plaques (r = -0.22, p = 0.01), and lower 6MWT (r = 0.34, p < 0.0001). Conclusion: FCR, an index of arterial reactivity obtained automatically using a novel, operator-independent device, was inversely associated with established CVD risk indices, increased number of carotid plaques, and lower cardiorespiratory fitness. Whether measuring FCR could play a role in screening for CVD risk and assessing whether endothelial function changes in response to treatments aimed at CVD risk reduction, warrants further study.

Laparoscopic cholecystectomy in a patient with a biventricular cardiac assist device.

Evaluation and management of abdominal pathology in patients with ventricular assist devices is likely to become increasingly important as the utilization of these devices expands. Ventricular assist devices represent a class of intracorporeal or paracorporeal mechanical devices that augment cardiac output in patients with congestive heart failure. Patients with ventricular assist devices supporting both right and left ventricles (biventricular assist devices) are uniquely challenging to the general surgeon because these devices restrict direct access to the abdominal cavity and because of the perioperative implications of biventricular heart failure. We describe herein the first reported successful laparoscopic cholecystectomy in a patient with a paracorporeal biventricular assist device. Cholecystectomy was performed in this patient for acute cholecystitis that occurred while the patient was awaiting heart transplantation. Our results add weight to the small body of evidence that laparoscopy is well tolerated in ventricular assist devices patients. The unique aspects of the biventricular assist device patient make laparoscopic abdominal intervention particularly suitable in this patient population.

In the current era, complete revascularization improves survival after coronary artery bypass surgery.

BACKGROUND: Complete revascularization has been the standard for coronary bypass grafting. However, surgical intervention has evolved with increasing use of arterial conduits and off-pump techniques. METHODS: Patients undergoing non-redo bypass surgery from January 1998 through December 2000 were followed up with questionnaires and telephone contact. Incomplete revascularization was defined as absence of bypass grafts placed to a coronary territory supplied by a vessel with 50% or greater stenosis. RESULTS: One thousand thirty-four patients were followed for a mean of 3.3 +/- 1.6 years. Complete revascularization was found in 937 (90.6%) patients, and incomplete revascularization was found in 97 (9.4%) patients. Eight hundred twenty-seven (80.4%) patients underwent on-pump operations, and 207 (19.6%) underwent off-pump operations. Incomplete revascularization was more prevalent in off-pump versus on-pump operations (21.7% vs 6.3%, P < .001). Multivariable Cox regression analysis indicated that in-hospital cerebrovascular accidents (hazard ratio, 5.49; P < .001), chronic obstructive pulmonary disease (hazard ratio, 1.97; P = .019), and incomplete revascularization (hazard ratio, 1.85; P = .040) predicted an increased hazard (risk) of cardiac death. Left internal thoracic artery (hazard ratio, 0.38; P = .047), right internal thoracic artery (hazard ratio, 0.25; P = .019), and radial artery (hazard ratio, 0.36; P < .001) grafting reduced the risk of cardiac death. The 5-year unadjusted survival rate was 52.6% versus 82.4% in patients undergoing incomplete and complete revascularization ( P < .001), with cardiac survival rates of 74.5% versus 93.1%, respectively ( P < .001). However, this difference in cardiac survival was smaller in octogenarians with incomplete versus complete revascularizations (77.4% vs 87.6%, P = .101) and was essentially absent in off-pump versus on-pump operations if complete revascularization was achieved in both cases (93.6% vs 93.1%, P > .200). CONCLUSIONS: Complete revascularization and arterial grafting improve 5-year survival. Off-pump techniques do not affect survival. Complete revascularization should be performed whenever possible.

Ischemic mitral regurgitation: revascularization alone versus revascularization and mitral valve repair.

BACKGROUND: In this study we compared the surgical management of ischemic mitral regurgitation (IMR) by revascularization alone and by revascularization combined with mitral valve repair. METHODS: We studied 355 patients who underwent revascularization alone (n = 168) or revascularization combined with mitral valve repair (n = 187) for IMR from March 1994 to September 2003. Preoperative and operative characteristics, postoperative mitral regurgitation severity, operative mortality, and late survival were examined for each surgical group. RESULTS: No differences were noted between the two groups in age, sex, history of diabetes or hypertension, and number of bypass grafts. The combined surgical group had a lower preoperative left ventricular ejection fraction (0.38 +/- 0.14 versus 0.44 +/- 0.15), greater severity of IMR, higher frequency of prior myocardial infarction, and longer cross-clamp and pump times (p < 0.01). The combined surgical group had a greater reduction in IMR grade (2.7 +/- 0.1 grades versus 0.2 +/- 0.1 grade), a lower postoperative IMR grade (0.9 +/- 0.1 versus 2.3 +/- 0.1), and a higher success with reduction of IMR by two or more grades (89% versus 11%) (p < 0.001). In patients with 3+ or 4+ IMR, both groups had similar operative mortality (11.0% in the combined group compared with 4.7% for revascularization alone, p = 0.11) and actuarial survival at 5 years (44% +/- 5% versus 41% +/- 7%, p = 0.53). Independently predictive of higher early mortality (< or = 30 days) by Cox analysis were longer pump time (p < 0.001) and older age (p < 0.02). Predictive of late mortality (> 30 days) were older age (p < 0.001), fewer bypass grafts (p < 0.01), and lower ejection fraction (p < 0.01). After adjustment for these variables, there was a trend (p = 0.08) toward a higher late survival with the combined surgical procedure. CONCLUSIONS: In patients with IMR, combined mitral valve repair and revascularization resulted in less postoperative mitral regurgitation and similar 5-year survival when compared with revascularization alone. Attempts to reduce pump time by using off-pump techniques may reduce early mortality in these high-risk patients.

A novel sub-population of bone marrow-derived myocardial stem cells: potential autologous cell therapy in myocardial infarction.

BACKGROUND: Several studies have identified beta2-microglobulin-negative (beta2M(-)) cells as a potential stem cell fraction in the bone marrow of rats and humans. We studied the ability of bone marrow-derived beta2M(-) cells to differentiate into cardiomyocytes and reconstitute the myocardium in a model of myocardial infarction. METHODS: beta2M(-) cells were purified from bone marrow of Lewis rats using a magnetic activated cell-sorting technique. beta2M(-) cells, 2.5 x 10(6) cells in 100 microl of phosphate-buffered saline (PBS), were transplanted 7 days after infarction into a transmural myocardial scar induced by cryoinjury in Lewis rats (n = 9). Control Group 1(n = 10) received a 100-microl injection of PBS, and Control Group 2 (n = 15) received no injection. The beta2M(-) cells were labeled before transplantation, using the membrane fluorescent intercalated dye, PKH26. Repopulation was examined at 6 and 8 weeks after transplantation. Differentiation of beta2M(-) cells into cardiac myocytes was determined by the colocalization of troponin and PKH26 to the same cell, utilizing immunohistochemistry, ultraviolet photomicroscopy and fluorescence microscopy on 6-microm serial sections. Area of engraftment within the scar was calculated by planimetry. RESULTS: The treatment group had multiple islands of de novo-formed myocardium within the fibrous matrix of the transmural scar (mean area 35 +/- 4.2% of scar area at 6 and 8 weeks). These cells colocalized cardiac-specific troponin and PKH26. Using these techniques, no myocardial islands were seen in the control groups. Before transplantation, beta2M(-) cells were troponin-negative. CONCLUSIONS: This study demonstrates that beta2M(-) cells represent a novel sub-population of bone marrow-derived stem cells capable of successful and substantial engraftment in areas of transmural myocardial scar, with de novo formation of cardiac myocytes. The functional significance of this observation is being studied.

Biventricular support in patients with profound cardiogenic shock: a single center experience.

Options for managing heart failure patients with cardiogenic shock refractory to inotropic and intra-aortic balloon pump (IABP) therapy are limited. Ventricular assist devices (VADs) can bridge these patients to heart transplantation. However, controversy exists over whether extracorporeal membrane oxygenation (ECMO) before VAD placement is beneficial. We report our use of biventricular assist devices (BiVADs) as a direct bridge to transplant. Since July 1999, 19 Thoratec BiVADs were implanted for heart failure unresponsive to medical therapy. Patient ages ranged from 20 to 67 years. Causes of heart failure included idiopathic 32%, ischemic 26%, postcardiotomy 21%, and other 21%. All patients were in cardiogenic shock, and three were receiving cardiopulmonary resuscitation (CPR) before implant. Preimplant conditions included IABP 89%, mechanical ventilation 68%, three or more inotropes 84%, hyperbilirubinemia 59%, acute renal failure 63%, and hemodialysis 16%. Fifty-nine percent of patients bridged successfully to transplantation, with 90% posttransplant survival. Duration of BiVAD support ranged from 0 to 91 days, with two patients currently on support awaiting transplantation. Complications included bleeding requiring reoperation 26%, stroke 11%, infection (any positive culture) 68%, and cannula site infection 5%. The Thoratec BiVAD can successfully be used as a direct bridge to transplantation in heart failure patients with cardiogenic shock.

Off-pump coronary surgery: effect on early mortality and stroke.

BACKGROUND: Avoiding cardiopulmonary bypass in coronary artery bypass grafting is thought to reduce early mortality and morbidity. METHODS: We used our prospective database to compare all patients having off-pump coronary surgery (n = 389) with those having on-pump coronary surgery (n = 2412) between March 15, 1995, and November 1, 2000. Patients were grouped by age (years) in decades (>90, 80-89, 70-79, 60-69, <60 years). The Northern New England risk model was applied. Thirty-two independent variables were entered into a stepwise logistic regression analysis with the end points being surgical mortality and postoperative stroke. RESULTS: Patients undergoing off-pump operations were older (70.9 +/- 12 vs 68.1 +/- 11 years; P <.001), and their Northern New England predicted risk was higher (11.9% +/- 13% vs 9.2% +/- 10%; P <.001). However, patients having on-pump bypass had significantly more bypass grafts constructed (3.3 +/- 0.8 vs 1.9 +/- 0.8; P <.001) and triple-vessel coronary artery disease (58% vs 28%; P <.001). There were no significant differences in postoperative mortality, stroke rate, complications, and length of stay between the groups. Logistic regression analysis did not show that cardiopulmonary bypass was a risk factor for either surgical mortality (odds ratio, 1.08; P =.83) or stroke (odds ratio, 1.59; P =.27). CONCLUSION: Off-pump coronary bypass did not reduce early mortality and morbidity. Early and late results should be compared in a prospective randomized study.

Heart transplantation with donors fifty years of age and older.

OBJECTIVE: Limited availability of donor organs has led to the progressive expansion of the criteria for donor selection, particularly a higher age limit of potential donors. We retrospectively reviewed the outcomes of patients who underwent heart transplantation using cardiac allografts 50 years of age and older and compared them with patients who had donor organs younger than 50 years. METHOD: Between September 1989 and May 2000, 20 patients underwent orthotopic heart transplantation using donor hearts 50 years of age and older (range 50-56 years, mean 52.7 +/- 1.8 years) and were compared with 267 patients who received donor organs less than 50 years of age (range 9-49.9 years, mean 27.2 +/- 8.6 years). Patient and donor criteria were identical in both groups. Follow-up was 4 to 128 months with a mean of 37.4 +/- 2.8 months in the older donor group and 52.6 +/- 2.4 months in the younger donor group. RESULTS: There were no differences between these 2 cohorts of patients regarding age, sex, cardiomyopathy, preoperative cytomegalovirus status, New York Heart Association class, and transplant status at transplantation. Donor characteristics, including sex, left ventricular ejection fraction, diabetes, cytomegalovirus status, and allograft ischemic times, were also similar in the 2 groups. Donor/recipient cytomegalovirus matching showed no differences as well. Thirty-day or to discharge operative mortality was similar in the older and younger donor groups (5% +/- 4.8% vs 3.5% +/- 1.1%; P =.84). Actuarial survival at 1 and 5 years was also similar in both groups (89.7% +/- 6.9% vs 91% +/- 1.8% and 53.1% +/- 14.7% vs 71.0% +/- 3.1%, respectively; P =.59). No patient in the older donor group required coronary artery bypass grafting or retransplantation during the follow-up period, whereas 2 patients in the younger donor group required coronary artery bypass, and 5 patients underwent retransplantation (P > or =.50). Two patients in the older donor group died of nonspecific allograft failure, whereas 3 patients in the younger donor group experienced similar posttransplant complication (P > or =.50). CONCLUSIONS: Carefully selected donor hearts 50 years of age and older can be used for heart transplantation with long-term survival and related outcomes similar to those of younger donor organs. This use of selective cardiac allografts maximizes donor organ usage and expands the donor pool effectively without an adverse impact on long-term results.