Mycotic false aneurysm of the ascending aorta.
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Aneurysm, False↗
Biomedical subjects
Stephen Westaby
Publications and source records attributed to Stephen Westaby.
Surgical restoration of the failing left ventricle.
As life expectancy increases in the Western world, heart failure (HF) is a major public health concern. Many patients with markedly reduced left ventricular ejection fraction can survive for years with reasonable functional capacity. Transplant-listed patients (LV) with ischemic heart disease who do not receive a donor organ may have a 3- to 4-year survival that equates with those transplanted. Thus, it is difficult to decide when to commit a patient with ischemic cardiomyopathy to transplantation unless supported by a LV assist device for cardiogenic shock. At the same time, the availability of donor organs is decreasing, with only 2000 per year in the United States and less than 300 in the United Kingdom. Consequently, there is a need to evaluate new surgical options for the deteriorating HF patient.
Heart Failure↗
Use of the Jarvik 2000 left ventricular assist system as a bridge to heart transplantation or as destination therapy for patients with chronic heart failure.
OBJECTIVE: To evaluate the Jarvik 2000 axial flow left ventricular assist system (LVAS) as a bridge to transplant and as destination therapy. SUMMARY BACKGROUND DATA: The Jarvik 2000 LVAS was implanted in 22 patients (16 men, 6 women; mean age 53 years) as a bridge to transplant (in the United States) and in 4 patients (all men; mean age 62.8 years) as destination therapy (in the United Kingdom). All patients in both of these initial feasibility studies were in NYHA class 4. METHODS: The pump was implanted through a thoracotomy or median sternotomy incision with the aid of partial cardiopulmonary bypass in bridge-to-transplant patients. A skull-mounted percutaneous power delivery was used for the patients who received the pump as destination therapy. RESULTS: Of the 22 bridge-to-transplant patients, 13 underwent transplant; 7 died during support; and 2 studies are ongoing. The surviving patients have an average follow-up of 15 months; one died at 2.6 months after transplant, and the remaining patients are all in NYHA class 1. Support averaged 67.1 days. Deaths were due to acute myocardial infarction in two patients and multiorgan failure in five patients. Hemodynamic function improved with LVAS support. The average cardiac index increased 70.6% by 48 hours after implant, pulmonary capillary wedge pressure decreased 44%, systemic vascular resistance decreased significantly, and inotropic support became unnecessary. Similar results have been seen in the patients who received the device as destination therapy. In that series, one patient died of subdural hematoma 380 days after implant. The other two patients are in NYHA class 1, 642 and 889 days after implant. The average cardiac index increased 89.5%, and pulmonary capillary wedge decreased 52.2%. CONCLUSIONS: The Jarvik 2000 axial-flow LVAS can be used safely in selected patients to provide support until transplant or as destination therapy. In this series, the patients who most benefited from this device were those who required true left ventricular assistance rather than total capture of left ventricular output. Current experience indicates that continuous offloading of the ventricle is most effective when there is enough residual myocardial function to maintain pulsatility and aortic root ejection and to maintain, with nonpulsatile pump support, a normal cardiac index as well as reinstitution of the Frank-Starling response to the native ventricle.
Adult↗
Initial clinical experience with the Jarvik 2000 implantable axial-flow left ventricular assist system.
BACKGROUND: Implantable left ventricular assist systems (LVASs) are used for bridging to transplantation, bridging to myocardial improvement, and for permanent circulatory support. Conventional implantable systems have inherent limitations that increase morbidity during support. In contrast, small, efficient, axial-flow pumps, which have been under development for the past decade, have the potential to improve the length and quality of life in patients with severe heart failure. Methods and Results- To assess the safety and clinical utility of the Jarvik 2000, we implanted this device in 10 transplant candidates (mean age 51.3 years) in New York Heart Association (NYHA) class IV. Implantation was achieved through a left thoracotomy during partial cardiopulmonary bypass. The mean support period was 84 days. Within 48 hours postoperatively, the cardiac index increased 43%, pulmonary capillary wedge pressure decreased 52%, systemic vascular resistance decreased significantly, and inotropic support became unnecessary. Eight patients underwent physical rehabilitation and returned to NYHA class I. Their left ventricular dimensions, cardiothoracic ratios, and pressure-volume loop analyses showed good left ventricular unloading. Seven patients underwent transplantation and 3 died during support. No device thrombosis was observed at explantation. CONCLUSIONS: The Jarvik 2000 functions as a true assist device by partially unloading the left ventricle, thereby optimizing the patient's hemodynamics. Our preliminary results indicate that this LVAS may safely provide circulatory assistance for heart transplant candidates.
Adult↗
Circulatory support for long-term treatment of heart failure: experience with an intraventricular continuous flow pump.
BACKGROUND: A lifetime mechanical solution for advanced heart failure must be reliable, with a low risk of life-threatening complications. After extensive laboratory testing, we began clinical trials with an axial flow pump for long-term treatment of New York Heart Association class IV, transplant-ineligible patients. METHODS AND RESULTS: The Jarvik 2000 is a continuous flow device that is implanted in the apex of the left ventricle with offloading to the descending thoracic aorta. Skull-based percutaneous power delivery was derived from cochlear implant technology. We used this system in 4 patients with end-stage dilated cardiomyopathy. Exercise capacity, quality of life, device parameters, and native heart function were monitored serially. One patient died from right heart failure at 3 months. The other patients were discharged from hospital between 3 and 8 weeks postoperatively and are currently New York Heart Association I or II. Follow-up lasted between 9 and 20 months. There has been no device failure or hemolysis. Native heart function and quality of life were markedly improved. CONCLUSIONS: The Jarvik 2000 is a true assist (rather than replacement) device that functions synergistically with the native left ventricle and provides excellent quality of life. Adverse events are infrequent. This blood pump may provide a mechanical solution for end-stage heart failure in the community.
Adrenergic beta-Antagonists↗
Acute type A dissection: conservative methods provide consistently low mortality.
BACKGROUND: A wide spectrum of operative techniques are applied in acute type A dissection. Most convey hospital mortality between 10% and 20%. In this high-risk setting, we believe that a conservative approach to the aortic root and the complete resection of the primary tear are important. We reviewed the results of this policy from our aortic surgery database. METHODS: Between 1988 and December 2000, 95 acute type A dissection patients were operated on by one surgeon. They included 70 men and 25 women aged 37 to 81 years (mean 65 years). Six had Marfan syndrome. Aortic root restoration or replacement was performed during cooling, open arch repair during circulatory arrest, and hemostasis while rewarming. Eighty-seven patients had ascending aortic replacement with glue resuspension of the valve. Two others had had aortic valve replacement previously. Aortic root and partial arch replacement was performed in 6 Marfan patients. Eighteen patients had hemiarch replacement, and 6 had total arch replacement to excise the tear. RESULTS: Five patients died in hospital (5.3% 30-day mortality) and another after early readmission for mediastinal infection (6.3% total mortality). There were no deaths from bleeding. Two patients required aortic valve replacement for aortic regurgitation 2.5 and 3.0 years postoperatively. Two others required total arch replacement and thromboexclusion procedures, respectively. CONCLUSIONS: Our policy of primary tear excision and preservation of the native aortic valve has resulted in low overall mortality. We still prefer to replace the aortic root in dissected Marfan patients. In this high-risk condition, hospital survival is of paramount importance. A conservative "pathology-oriented" approach helps to achieve this aim.
Adult↗
Implant technique for the Jarvik 2000 Heart.
The Jarvik 2000 Heart is a silent compact axial flow impeller pump which is now undergoing clinical trials for both bridge to transplantation and permanent mechanical circulatory support. The pump is implanted into the apex of the failing left ventricle by left thoracotomy. A vascular graft offloads to the descending thoracic aorta so that only the left pleural cavity is opened. Power supply is through an abdominal drive line or postauricular titanium pedestal according to the treatment strategy.
Heart, Artificial↗
End-organ function during chronic nonpulsatile circulation.
BACKGROUND: Evolving blood pump technology has produced user-friendly continuous flow left ventricular assist devices, but uncertainty exists about the safety of chronic nonpulsatile circulation. We established consistently nonpulsatile blood flow in a sheep model using the Terumo magnetically suspended centrifugal pump. We then compared end-organ function between pulseless and control animals. METHODS: Fifteen healthy sheep (65 to 85 kg) were allocated to either left ventricular assist device (n = 9) or control (n = 6) groups. We implanted the device through a left thoracotomy and determined the flow rate at which pulse pressure was absent. The flow rate was then adjusted to exceed that rate (4.2 +/- 1.5 L/min), and all variables of pump function were continuously monitored by computer. Blood tests were taken serially for hepatic and renal function and plasma renin levels. The sheep were sacrificed electively at 30 (n = 3), 90 (n = 4), 180 (n = 1), and 340 (n = 1) days. Detailed histologic examination was made of the brain, liver, kidney, myocardium, and major arteries. RESULTS: All animals remained in good condition until sacrifice. All measures of end-organ function remained within normal limits for both groups. There were no histologic differences between the organs of pulsatile and nonpulsatile animals. Although there was no significant difference in mean blood pressure, plasma renin levels were substantially elevated in pulseless animals (1.4 +/- 0.3 pg/mL versus 2.9 +/- 0.3 pg/mL; p < 0.05). We also identified thinning of the medial layer of the ascending aorta in nonpulsatile sheep (1.8 +/- 0.4 mm in left ventricular assist device animals versus 2.6 +/- 0.6 mm in control sheep; p < 0.05). CONCLUSIONS: Chronic nonpulsatile circulation was well tolerated, and we found neither functional nor histologic changes in major end organs. The renin-angiotensin system was upregulated, but this did not provide a significant rise in blood pressure. The changes in the aortic wall merit further investigation. As a result of these findings, we consider that nonpulsatile devices can be used safely for long-term circulatory support.
Animals↗
Aortic root remodeling in atheromatous aneurysms: the role of selected sinus repair.
OBJECTIVE: Atheromatous ascending aortic aneurysms (AAA) frequently present with aortic regurgitation (AR) from dilatation of the sino-tubular junction (STJ) and extension of the pathological process into the root. Experience suggests that root dilatation begins in the non-coronary, then right coronary sinus. Rather than employ aortic root replacement or the David procedure, we have elected to replace the ascending aorta and remodel the STJ and involved sinuses. We studied the outcome after selective sinus replacement in 29 consecutive AAA patients between 1995 and 2001. METHODS: There were nine male and 20 females. Age ranged from 47 to 79 years (mean 67.5). Seven had arch aneurysms and four coronary artery disease. Nineteen were NYHA III or IV. Grade of AR was IV in 20, III in five and II in four. The STJ was dilated >50% of annulus diameter in each case (5.3-10.0 cm, mean 6.4 cm). All valves had three cusps. All patients underwent ascending aortic replacement. Seven had arch replacement and four coronary artery bypass. Seven had replacement of both right and non-coronary sinuses with re-implantation of the right coronary ostium. Twelve had replacement of the non-coronary sinus alone whilst nine had right coronary sinus replacement. One with dextrocardia had left coronary sinus replacement with ostial re-implantation. The graft size was within 2 mm of annulus size except for two patients (24 mm 12, 26 mm 11, and 28 mm six). Post operative echocardiographic studies were performed. None of the patients received anticoagulation. RESULTS: There were no hospital or late deaths and no thromboembolic or infective complications. Two patients had mild to moderate aortic regurgitation. These had a size 28 graft, which in retrospect was too large. Others had no significant regurgitation. CONCLUSIONS: The native aortic valve can be preserved in the majority of patients with AAA. Remodelling of the STJ and selective sinus replacement restores valve competence. Anticoagulation and prosthesis related complications are thereby avoided.
Aged↗
The Jarvik 2000 Heart. Clinical validation of the intraventricular position.
OBJECTIVE: Heart failure is now a public health epidemic. Donor hearts are severely restricted in availability. Permanent mechanical circulatory support or bridge to myocardial recovery are emerging alternatives. After extensive laboratory experience we sought to evaluate the intraventricular Jarvik 2000 Heart in patients with endstage heart failure. METHODS: The Jarvik 2000 Heart is a novel thumb-sized left ventricular assist device (LVAD) which is fitted within the apex of the native left ventricle. A vascular graft off loads this to the descending thoracic aorta. The pump rotor spins at between 8000 and 12,000 rpm providing 5-6 litres blood flow per minute. We have used the device with skull-mounted power delivery for seven permanent implants and trans-abdominal drive line for ten bridge-to-transplant patients. RESULTS: All patients survived the operation. Three died from non-device related complications. Survivors had early resolution of heart failure with return to NYHA I/II. All had pulsatile circulation. The device was user-friendly and imperceptible to the patient. Both the pump and native left ventricle contributed to the cardiac output during exercise. Seven patients have been transplanted successfully. All explanted devices were free from thrombus formation. Two permanent implant patients left hospital as early as 3 weeks postoperatively. CONCLUSIONS: The Jarvik 2000 is an effective user-friendly LVAD which allows early discharge from hospital. The intraventricular position has distinct advantages especially through absence of an inflow cannula. Synergy develops between the LVAD and native left ventricle. Early experience suggests that this may be a realistic LVAD to treat heart failure routinely in the outpatient setting.
Adult↗
Postauricular percutaneous power delivery for permanent mechanical circulatory support.
OBJECTIVE: Percutaneous driveline infection continues to detract from both quality and length of life in patients with a left ventricular assist device. We have pursued an alternative route by using a skull-mounted percutaneous pedestal similar to cochlear implant technology. We have now used this method in patients implanted with the Jarvik 2000 heart (Jarvik Heart, Inc, New York, NY) as destination therapy for end-stage (New York Heart Association class IV) heart failure. METHODS: Four men with cardiomyopathy aged 61 to 72 years received the Jarvik 2000 heart with postauricular power delivery for permanent mechanical circulatory support. The power cable was brought through the second posterior intercostal space and routed through the neck to a percutaneous titanium implant screwed to the skull. This joins with the cable to the external controller and battery. RESULTS: In 3 patients the pedestal healed well and remained free from infection up to 1 year. The system was user friendly, and the whole external apparatus is exchangeable. The second patient had a subdural hematoma. This caused us to improve the preparation and modify the implant procedure. CONCLUSION: For widespread use, permanent implantable circulatory support requires a reliable, user-friendly device with freedom from powerline infection. Our early experience with the Jarvik 2000 heart suggests that rigid fixation and the vascularity of scalp skin promote healing and reduce the risk of driveline infection.
Aged↗
Current diagnostic strategies in heart failure.
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Cardiomyopathies↗