Median arcuate ligament syndrome: Use of fractional flow reserve in documentation of chronic mesenteric ischemia

Median arcuate ligament syndrome (MALS) is a rare clinical entity. This condition typically affects women between the ages of 20 and 40 years and causes symptoms of abdominal pain, primarily post-prandial, as well as nausea, vomiting and weight loss. MALS is considered a diagnosis of exclusion. Typically, mesenteric arterial duplex ultrasonography, computed tomography (CT), and magnetic resonance (MR) are highly suggestive, and conventional contrast angiography confirmatory. We explore the role of fractional flow reserve and intravascular ultrasound in the evaluation of MALS. In order to illustrate the utility of these tools, we present the case of a 47-year-old symptomatic woman who underwent angiography, complemented by assessment of fractional flow reserve and intravascular ultrasound. These data convincingly demonstrated the dynamic nature of the obstructive characteristic of MALS.

Acute massive pulmonary embolism with cardiopulmonary resuscitation: management and results

Patients who experience hemodynamic collapse after acute massive pulmonary embolism have a poor prognosis. Herein, we report our results with 8 patients and discuss a surgical strategy that can improve perioperative survival. From August 1994 through May 2005, 8 consecutive patients (6 women, 2 men; age range, 27-68 yr) were urgently referred to our unit after experiencing hemodynamic collapse. All required cardiopulmonary resuscitation. Seven patients underwent pulmonary embolectomy. One patient was successfully treated with thrombolytic therapy alone under continuous monitoring by the surgical team. There were 2 intraoperative deaths (30-day mortality rate, 28.5%). One survivor required a right ventricular assist device. Follow-up of the patients ranged from 8 months to 8 years. One patient died 8 months after the pulmonary embolectomy from long-term complications of cerebral damage that had occurred during preoperative resuscitation. We conclude that prompt surgical management improves the early survival rates of patients who require cardiopulmonary resuscitation subsequent to massive pulmonary embolism.

In vivo evaluation of the HeartWare centrifugal ventricular assist device

In this study, long-term (90-day) hemocompatibility and end-organ effects of a centrifugal left ventricular assist device (the Heartware HVAD) were evaluated in 6 healthy sheep. The device was implanted into the left ventricular apex on beating hearts. The outflow graft of each device was anastomosed to the descending aorta. None of the sheep received anticoagulation or antiaggregation medication during the study. Hematologic and biochemical tests of liver and kidney function were performed pre-operatively (baseline) and throughout the study. Data associated with pump function were collected continuously until 90 +/- 1 days of support, at which time the sheep were humanely killed, and the end-organs were examined macroscopically and histopathologically. Hematologic and biochemical test results were within normal limits during the study period. There were no significant complications. Postmortem examination of the explanted organs revealed no evidence of ischemia or infarction, except in 2 sheep, in which small foci of infarction were detected in each of their left kidneys. There was no significant device failure. In all sheep, the pump's inflow and outflow conduits were free of thrombus. During the 90-day study, the HeartWare HVAD showed exceptional hemocompatibility and reliability, both of which are crucial to the clinical success of any implantable left ventricular assist device.

Cardiac tamponade revisited: a postmortem look at a cautionary case

Cardiac tamponade is a life-threatening clinical syndrome that requires timely diagnosis. Herein, we present an instructive case of a patient who had cardiac tamponade. The condition went undiagnosed and resulted in the patient's death because almost all of the pathognomonic clinical findings of tamponade were unrecognized or not manifest. To better prepare health care professionals for similar challenges, we discuss the symptoms and clinical signs typical of cardiac tamponade, review the medical literature, and highlight current investigative methods that enable quick, efficient diagnosis and treatment.

Initial clinical experience with the HeartMate II axial-flow left ventricular assist device

The redesigned HeartMate II, an axial-flow left ventricular assist device, is simpler, smaller, and easier to operate than are pulsatile pumps. These design characteristics should make the HeartMate II more reliable and durable and broaden the eligible population base. We implanted the HeartMate II in 43 patients (average age, 42 yr). The indication for use was bridge-to-heart transplantation in 26 patients and destination therapy in 17. The average duration of device support was 258 days (range, 1-761 days), and cumulative duration, more than 31 patient-years. Hemodynamic function improved in all patients during support. By 48 hours after implantation, the mean cardiac index had increased from 1.9+/-0.27 L/(min.m(2)) (baseline) to 3.5+/-0.8 L/(min.m(2)), and the pulmonary capillary wedge pressure had decreased from 24.8+/-11 mmHg to 18.5+/-5.3 mmHg. Of the 43 patients, 35 were discharged from the hospital. Support is ongoing in 27 patients (longest duration, >700 days). Nine patients died during support. Four patients had sufficient heart recovery to undergo pump explantation. Three patients underwent transplantation. One patient underwent device replacement after the pump driveline was fractured in a skateboarding accident; the device was removed in another patient because of a pump-pocket infection after 749 days of support. Of the 10 patients in whom the HeartMate II replaced a failed HeartMate I, 8 were discharged from the hospital. We have seen excellent results with use of the HeartMate II. Functional status and quality of life have greatly improved in patients who survived the perioperative period.

Percutaneous ventricular assist during aortic valvuloplasty: potential application to the deployment of aortic stent-valves

We evaluated the short-term safety and efficacy of using the TandemHeart(R) percutaneous ventricular assist device in high-risk patients undergoing aortic valvuloplasty procedures. Aortic valvuloplasty was performed in 4 patients who had no ventricular assist device support and in 7 patients who used the TandemHeart for hemodynamic support. The age range was 65 to 94 years (mean, 83 +/- 11 yr). The mean ejection fraction was 0.30 +/- 0.14. A transseptal antegrade approach to the aortic valve was used in 8 patients and a retrograde approach in the remaining 3. WITH THE TANDEMHEART, ALL PROCEDURES WERE TECHNICALLY SUCCESSFUL: each patient survived at least 1 month after the procedure. The mean total balloon inflation time was 37 +/- 10 sec. The aortic valve area was 0.6 +/- 0.1 cm(2) before the procedure and 0.9 +/- 0.2 cm(2) afterwards (P=0.006). Without TandemHeart support, 1 patient died of cardiac arrest during the procedure. The mean total balloon inflation time was 11 +/- 3 sec. Aortic valve area was 0.6 +/- 0 cm(2) before the procedure and 1.1 +/- 0.3 cm(2) afterwards (P=0.3). No patient developed aortic regurgitation. We conclude that use of the TandemHeart for hemodynamic support during high-risk aortic valvuloplasty is associated with favorable intraprocedural and short-term outcomes. With the TandemHeart in place, balloon placement was precise, and inflation was maintained for up to 45 sec without balloon displacement. These attributes are essential during stent-valve placement, are achieved without rapid ventricular pacing, and may reduce the risk of global ischemia and death.

Clinical experience with the TandemHeart percutaneous ventricular assist device

The TandemHeart percutaneous ventricular assist device can be used to support patients in cardiogenic shock (until cardiac recovery occurs or as a bridge to definitive therapy) or as a temporary application during high-risk coronary interventions. The TandemHeart is a left atrial-to-femoral artery bypass system comprising a transseptal cannula, arterial cannulae, and a centrifugal blood pump. The pump can deliver flow rates up to 4.0 L/min at a maximum speed of 7500 rpm. From May 2003 through May 2005, the TandemHeart was used to support 18 patients (11 in cardiogenic shock and 7 undergoing high-risk percutaneous transluminal coronary angioplasty). The patients in cardiogenic shock were supported for a mean of 88.8 +/- 74.3 hours (range, 4-264 hr) at a mean pump flow rate of 2.87 +/- 0.56 L/min (range, 1.8-3.5 L/min). The mean cardiac index improved from 1.57 +/- 0.31 L/min/m2 before support to 2.60 +/- 0.34 L/min/m2 during support. The mean duration of support for the high-risk percutaneous transluminal coronary angioplasty patients was 5.5 +/- 8.3 hours (range, 1-24 hr). The mean flow rate was 2.42 +/- 0.55 L/min (range, 1.5-3.0 L/ min). The overall 30-day survival rate was 61%. In our experience, the TandemHeart device was easy to insert and provided a means either to cardiac recovery or to continued support with an implantable left ventricular assist device.

Open-chest management after heart transplantation

Postcardiotomy open-chest management has been widely used in cardiac surgery. Although this strategy can be applied to heart transplantation, the use of immunosuppressants in transplant recipients raises particular concerns about sternal wound infection and impaired healing. We performed a retrospective review of 403 patients who had undergone 410 heart transplantations at our institution from 1985 through 2004. Among them, 9 patients (2.2%) had open-chest management postoperatively. There were 8 men and 1 woman, with a mean age of 58 +/- 7 years. The graft ischemic time ranged from 130 to 374 minutes (mean, 218 +/- 99 min), and the cardiopulmonary bypass time ranged from 98 to 360 minutes (mean, 210 +/- 69 min). In all cases, the reason for open-chest management was hemodynamic lability that precluded chest closure after transplantation. One patient also experienced postoperative bleeding. All patients underwent delayed sternal closure between postoperative days 1 and 11 (median, 4 days). Delayed sternal closure did not cause any significant hemodynamic changes. One patient died of stroke on postoperative day 22. No patient had sternal wound infection or impaired wound healing during the follow-up period. We conclude that, when required, open-chest management is an effective and safe measure for hemodynamically unstable heart transplant patients.

Acute smoking-induced alterations in Doppler echocardiographic measurements in chronic smokers

Acute effects of smoking on left ventricular function have been studied previously. However, effects on right ventricular function have not yet been investigated. In this study, we attempted to investigate, through a combination of conventional and tissue Doppler imaging (TDI), the acute effects of smoking on both left and right ventricular function in chronic smokers. Thirty chronic smokers (with smoking habits of > or =1 pack/day for 74 +/- 1.3 years) underwent a complete transthoracic echocardiographic examination (2-dimensional, pulsed-wave Doppler transmitral and transtricuspid recordings, and TDI recordings of mitral and tricuspid annular velocities) by 3.5-MHz sector transducer. Pulsed-wave Doppler indices of left and right ventricular diastolic function-such as mitral and tricuspid inflows, peak early (E) and late (A) velocities, and E/A ratios-were obtained by conventional Doppler and TDI. Echocardiographic indices of the left and right ventricles--including isovolumetric relaxation time, isovolumetric contraction time, ejection time, and myocardial performance index of right ventricle-were also measured before and 30 minutes after each subject smoked a cigarette. Both mitral and tricuspid inflow measurements changed significantly after smoking a cigarette. Among the TDI measurements, mitral lateral annulus and tricuspid lateral annulus (diastolic, but not systolic) velocities changed after smoking a cigarette. Also, the right ventricular myocardial performance index increased immediately after smoking a cigarette. We found that acute cigarette smoking impaired both left and right ventricular diastolic function in chronic smokers.

Effects of previously well-developed collateral vessels on left internal mammary artery graft flow after bypass surgery

Transthoracic Doppler ultrasonography can assess left internal mammary artery patency and flow after coronary artery bypass grafting. We aimed to show, by transthoracic Doppler ultrasonography, the early effects upon left internal mammary artery graft flow of preoperative collateral vessels supplying the left anterior descending artery. Thirty-four consecutive patients undergoing coronary artery bypass were prospectively enrolled: 19 patients with collateral vessels supplying the left anterior descending were compared with 15 patients without collaterals. After bypass, end-diastolic velocity, mean velocity, flow volume, and ejection fraction were significantly greater, and the resistivity index was lower in patients with collateral vessels. The changes in velocities, volume, resistivity index, and pulsatility index were also found to be greater in patients with collateral vessels than in those without collaterals. Collateral vessels were the only factor affecting the changes in end-diastolic volume, mean velocity, flow volume, and resistivity index in multivariate analysis. Three factors affected postoperative left ventricular ejection fraction: collateral vessels, preoperative ejection fraction, and changes in left internal mammary flow volume. We conclude that patients with well-developed collaterals to the left anterior descending have better flow in the left internal mammary graft and more significant improvement in left ventricular function after coronary bypass. The flow volume of the mammary graft and the improvement of ventricular systolic functions after coronary bypass might be presumed with the presence of grade 2 or 3 preoperative collateral vessels.

Development of an animal experimental model for a bileaflet mechanical heart valve prosthesis

The objective of this study was to develop a pre-clinical large animal model for the in vivo hemodynamic testing of prosthetic valves in the aortic position without the need for cardiopulmonary bypass. Ten male pigs were used. A composite valved conduit was constructed in the operating room by implanting a prosthetic valve between two separate pieces of vascular conduits, which bypassed the ascending aorta to the descending aorta. Prior to applying a side-biting clamp to the ascending aorta for proximal grafting to the aortic anastomosis, an aorta to femoral artery shunt was placed just proximally to this clamp. The heart rate, cardiac output, Vmax, transvalvular pressure gradient, effective orifice area and incremental dobutamine stress response were assessed. A dose-dependent increase with dobutamine was seen in terms of cardiac output, Vmax, and the peak transvalvular pressure gradient both in the native and in the prosthetic valve. However, the increment was much steeper in the prosthetic valve. No significant differences in cardiac output were noted between the native and the prosthetic valves. The described pre-clinical porcine model was found suitable for site-specific in-vivo hemodynamic assessment of aortic valvular prosthesis without cardiopulmonary bypass.

Transcatheter closure of a patent foramen ovale in an adult with hypoxemia after cardiac transplantation

We describe a case of refractory hypoxemia secondary to a patent foramen ovale immediately after orthotopic heart transplantation in a 60-year-old woman. The patent foramen ovale was successfully closed with a septal occlusion device, with resolution of the hypoxemia. To our knowledge, transcatheter closure of a patent foramen ovale in an adult patient with refractory hypoxemia during the immediate post-transplant period has not previously been reported.