Chronic extra-aortic balloon counterpulsation: first-in-human pilot study in end-stage heart failure

BACKGROUND

Some patients continue to have significant heart failure symptoms despite optimal medical therapy.

METHODS

We describe a first-in-human experience with an implantable non-blood-contacting extra-ascending aortic counterpulsation heart assist system (C-Pulse) in 5 end-stage heart failure patients, aged 54 to 73 years.

RESULTS

All patients improved by 1 NYHA class and improvements in invasive hemodynamics were documented in 3 patients. Three of 5 patients (60%) had infectious complications. Two patients were explanted at 5 and 7 weeks, respectively, as a result of mediastinal infection related to the implant procedure. One patient was successfully transplanted at 1 month and 1 remained hemodynamically improved on the device at 6 months but suffered infective complications. The device and protocol have been modified as a result of this pilot study with a further multicenter safety study underway.

CONCLUSIONS

Although feasibility of this device is suggested by this pilot study, safety and efficacy will need to be examined in a larger cohort with longer follow-up.

Consensus statement: minimal criteria for reporting the systemic inflammatory response to cardiopulmonary bypass

The lack of established cause and effect between putative mediators of inflammation and adverse clinical outcomes has been responsible for many failed anti-inflammatory interventions in cardiopulmonary bypass (CPB). Candidate interventions that impress in preclinical trials by suppressing a given inflammation marker might fail at the clinical trial stage because the marker of interest is not linked causally to an adverse outcome. Alternatively, there exist examples in which pharmaceutical agents or other interventions improve clinical outcomes but for which we are uncertain of any antiinflammatory mechanism. The Outcomes consensus panel made 3 recommendations in 2009 for the conduct of clinical trials focused on the systemic inflammatory response. This panel was tasked with updating, as well as simplifying, a previous consensus statement. The present recommendations for investigators are the following: (1) Measure at least 1 inflammation marker, defined in broad terms; (2) measure at least 1clinical end point, drawn from a list of practical yet clinically meaningful end points suggested by the consensus panel; and(3) report a core set of CPB and perfusion criteria that maybe linked to outcomes. Our collective belief is that adhering to these simple consensus recommendations will help define the influence of CPB practice on the systemic inflammatory response, advance our understanding of causal inflammatory mechanisms, and standardize the reporting of research findings in the peer-reviewed literature.

Extra-aortic implantable counterpulsation pump in chronic heart failure

Extra-aortic counterpulsation for the management of chronic heart failure is a novel approach. We report the use of an extra-aortic implantable counterpulsation pump in the management of a 73-year-old patient with severe heart failure refractory to medical therapy. The implantable counterpulsation pump prolonged his life and greatly improved its quality. The patient lived almost 7 months after the implantation of the device and died of septic complications secondary to gas line infection.

Extra-aortic balloon counterpulsation: an intraoperative feasibility study

BACKGROUND

Current methods of counterpulsation or ventricular assistance have significant vascular and limb complications. The aim of this study was to determine the safety and performance of a new method of non-blood-contacting counterpulsation using an inflatable cuff around the ascending aorta (extra-aortic balloon [EAB]).

METHODS AND RESULTS

In 6 patients undergoing first time off-pump coronary bypass surgery via sternotomy, the EAB was secured around the ascending aorta and attached to a standard counterpulsation console. At baseline and with 1:2 and 1:1 augmentation, hemodynamic and echocardiographic parameters of ventricular function and coronary flow were measured. High-intensity transient signals were measured using transcutaneous Doppler over the right common carotid artery. No complications occurred. With EAB there was no significant change in heart rate or blood pressure and no increase in high-intensity transient signals. There was a 67% increase in diastolic coronary blood flow (mean left-main diastolic velocity time integral 15.3 cm unassisted versus 25.1 cm assisted, P<0.05). Measurements with transesophageal echocardiography at baseline and with 1:1 counterpulsation demonstrated a 6% reduction in end-diastolic area (P=NS), a 16% reduction in end-systolic area (P<0.01), a 31% reduction in left ventricular wall stress (P<0.05), and a 13% improvement in fractional area change (P<0.005).

CONCLUSIONS

EAB counterpulsation augments coronary flow and reduces left ventricular afterload. Further testing is warranted to assess the use of the EAB for chronic non-blood-contacting support of the failing heart.

Extra-Ascending Aortic Versus Intra-Descending Aortic Balloon Counterpulsation—Effect on Coronary Artery Blood Flow

BACKGROUND

Diastolic counterpulsation has been used to provide circulatory augmentation for chronic heart failure or for short-term cardiac support. Recently an extra-aortic balloon (EAB) counterpulsation device has been proposed.

AIM

To compare the circulatory effects of counterpulsation using the EAB or an intra-aortic balloon (IAB) in the acute pig model.

METHODS

In six anaesthetized great white pigs (paced at 100 bpm), ECG, arterial and central venous pressures, flow in the coronary circulation and descending thoracic aorta were measured. Baseline data was collected, then with the EAB or an IAB fitted using 1:1 and 1:2 counterpulsation modes. Baseline data was compared to EAB and IAB data in 1:1 mode. Assisted beat data compared to unassisted beat data was also analysed in 1:2 mode.

RESULTS

Both devices augmented peak diastolic arterial pressure, and decreased afterload. EAB counterpulsation increased diastolic coronary flow in both the 1:1 mode by 69% (p < 0.05) and in the 1:2 mode by 63% (assisted versus unassisted beat, p < 0.05). The IAB significantly increased diastolic coronary flow only in the 1:2 mode by 28% (p < 0.01). Both devices augmented total coronary flow and some augmentation of aortic flow was observed.

CONCLUSION

The circulatory effect of the EAB and IAB counterpulsation were comparable. This suggests the EAB could be used as a non-blood contacting heart assist device in patients suffering moderate-severe heart failure.

Cardiopulmonary bypass in pregnancy: possible new role for the intra-aortic balloon pump

Cardiopulmonary bypass (CPB) during pregnancy is associated with a maternal mortality similar to the nonpregnant population; however, fetal morbidity and mortality are high. Various strategies to improve fetal survival have been advocated. Alteration in uterine artery flow velocity has been reported during nonpulsatile CPB; however, roller pump-generated pulsatile flow for CPB remains controversial. We report use of the intra-aortic balloon pump (IABP) in two cases of pregnancy. In the first, the IABP was inserted after termination of a long bypass, specifically in an attempt to improve uterine perfusion and thereby relieve a profound fetal bradycardia. In the second, the IABP was used electively to provide pulsatile flow during the bypass period primarily to benefit fetal hemodynamics.

Asymmetric primary ringless repair of mitral valve endocarditis: a case report

The case is presented of a patient with a large mitral valve vegetation. A technique of mitral valve repair involving ringless annuloplasty repair following bileaflet resection of the infected regions of the valve is described. No pledgets or prosthetic material were used in the repair. The patient recovered uneventfully, with trivial mitral regurgitation documented on post-repair echocardiography. This technique may suggest a method for early intervention in mitral endocarditis.

Physical and Pharmacological Neuroprotection in Cardiac Surgery

Stroke and neurocognitive deficits may follow cardiac surgery and have been linked to perioperative cerebral embolism. Alteration of cardiopulmonary bypass (CPB) or surgical technique to reduce embolism is, therefore, a rational neuroprotective strategy. Pharmacological cerebral protection has been advocated as an ideal "back-stop" to such "physical" interventions. A series of relevant studies conducted at Green Lane Hospital, Auckland, New Zeatand is described. Doppler ultra sound was used to monitor cerebral embolism during left heart valve surgery. Subsequently, salvaged CPB circuits were used to investigate several unexpected sources of emboli. The efficacy of a novel left heart deairing technique was audited using the Doppler de vice. Finally, a randomized double-blind trial of lidocaine in cerebral protection during cardiac surgery was con ducted. Most cerebral emboli were recorded after aortic declamping. However, cerebral emboli counts increased during stable CPB when the hard shell venous reservoir (HSVR) was operated at lower blood volumes and when air was seen in the venous return line. In vitro 2 HSVRs were found to generate bubbles when operated at blood volumes in excess of the manufacturer's recom mended minimum. Air in the venous return line was found to readily transit the CPB circuit and vacuum- assisted venous drainage markedly exacerbated this phenomenon. The novel deairing technique was mark edly superiorto conventional methods. Lidocaine admin istered in a standard antiarrhythmic dose for 48 hours from induction of anesthesia reduced the incidence of neuropsychological deficits at 10 days and 10 weeks postoperatively.

Early experience with the mosaic bioprosthesis: a new generation porcine valve

BACKGROUND

The Mosaic bioprosthesis is a new generation stented porcine valve.

METHODS

Between May 1995 and April 1998, this valve was implanted in the aortic position in 98 patients (70 men; mean age, 69.2 years [34.2 to 83.6 years]). Preoperatively 35 patients were in New York Heart Association functional class 3 or 4. Fifty-nine patients underwent concomitant procedures. The mean duration at follow-up in January 1999 was 23.7 +/- 10.2 months (0.3 to 39.4 months) and totaled 193 patient-years. All but one survivor was in New York Heart Association class 1 or 2.

RESULTS

Early complications included 1 death, 3 reoperations for bleeding, greater than mild regurgitation (paravalvar) in 1 patient and thromboembolism in 4 patients. Late complications included four deaths, study-valve endocarditis in 3 patients, more than mild regurgitation or hemolysis in 2, and thromboembolism in 2 patients. Late follow-up echocardiography in all survivors showed a mean transaortic gradient of 13.6 +/- 6.7 mm Hg, and an aortic valve area of 1.80 +/- 0.61 cm2. Valve replacement was followed by a significant and sustained decrease in left ventricular mass for all valve sizes. There has been no primary structural valve failure.

CONCLUSIONS

The early experience with the Mosaic valve in the aortic position has been promising.

A dual-vent left heart deairing technique markedly reduces carotid artery microemboli

BACKGROUND

Cerebral embolization, mainly bubbles, follows aortic declamping in left heart valve operations. Embolization is not prevented by conventional left heart deairing methods. We have validated a "dual-vent" deairing technique, which uses high-flow left ventricular and aortic venting from the working heart into the cardiopulmonary bypass venous line before aortic declamping.

METHODS

After left heart valve replacement, intraoperative color-flow Doppler echocardiography was used to monitor the right common carotid embolic activity in 58 consecutive patients who underwent conventional deairing (group 1), 14 consecutive patients who underwent deairing by the dual-vent technique (group 2), and 4 patients who received nonvented coronary artery bypass grafting who did not require deairing (group 3).

RESULTS

The median emboli count recorded after aortic declamping was 1,647 (range, 342 to 6,852) and 101 (range, 0 to 865) in the group 1 and 2 patients, respectively (p < 0.0001). The efficacy of the dual-vent technique improved throughout the series: in the last 7 patients, the emboli counts often approached the very low levels seen in group 3 patients (median, 8; range, 1 to 16).

CONCLUSIONS

Cerebral embolization after aortic declamping in left heart valve operations was significantly reduced by this dual-vent deairing technique.

Coronary revascularisation in young adults

OBJECTIVE

To evaluate the long-term outcome of coronary artery bypass surgery (CABG) in patients < 40 years old and to determine factors predictive of adverse outcomes.

METHODS

Retrospective review of data on 220 patients who underwent isolated CABG at Green Lane Hospital, New Zealand from 1970 to 1992.

RESULTS

The actuarial survival after surgery was 91, 74 and 50% at 5, 10 and 15 years, respectively. Recurrence of ischaemic symptoms occurred at a median time of 72 months, and only 20% of patients remained asymptomatic 10 years after CABG. Univariate analysis of potentially adverse surgical factors showed that patients who had prolonged bypass time (> or = 100 min, P < 0.007) had increased late mortality. There were two distinct operative eras with respect to the use of IMA conduits (4% pre 1985, 87% post 1984) The relationship between IMA conduits use and survival was significant on time independent analysis (P < 0.02), but was not using the log-rank test. Preoperative clinical characteristics associated with increased late mortality were impaired left ventricular function (end-systolic volume (ESV) > or = 80 ml, P = 0.008; ejection fraction < 40%, P = 0.0005), and lack of aspirin use either pre- or post-operatively (P < 0.0001). Multivariate analysis indicated that reduced ejection fraction (P = 0.04) and prolonged bypass time (P = 0.05) was associated with an increased risk of late death. Aspirin therapy (P = 0.001) was associated with decreased late mortality. Cumulative events rate of reintervention and mortality was reduced in female patients (P = 0.0009). At review, 45% of patients had total cholesterol > 6.5 mmol/l.

CONCLUSION

To avoid the early recurrence of symptoms, the need for reintervention and late mortality, young patients should receive IMA conduits, cardioplegia as myocardial protection, aspirin and therapy to modify/ameliorate their risk factors including dyslipidaemia, diabetes and left ventricular dysfunction.

Aortic valve replacement and mitral valve repair with allograft

Techniques of repair of defects in the anterior leaflet of the mitral valve and replacement of the aortic valve using allograft are presented. The case history and operative procedure of a reconstructive operation that did not require anticoagulant therapy after surgery are described for three adult patients. Mitral valve defects were repaired using the anterior leaflet of the mitral valve of the allograft. The aortic valve or entire root was replaced with the aortic allograft. The aortic/mitral allograft should be considered as an alternative to replacement of the aortic and mitral valves with prostheses in selected patients.

Acute streptococcal necrotising fasciitis

Two cases of acute streptococcal necrotising fasciitis are reported. Both patients were taking nonsteroidal antiinflammatory drugs when they developed this infection. Urgent surgical debridement was undertaken and resulted in a successful outcome in both patients. The clinical and histopathological features of this condition are reviewed.