Arterio-venous gradients of free energy change for assessment of systemic and splanchnic perfusion in cardiac surgery patients

OBJECTIVE: Adequacy of organ perfusion depends on sufficient oxygen supply in relation to the metabolic needs. The aim of this study was to evaluate the relationship between gradients of free energy change, and the more commonly used parameter for the evaluation of the adequacy of organ perfusion, such as oxygen-extraction in patients undergoing valve replacement surgery using normothermic cardiopulmonary bypass (CPB). METHODS: In 43 cardiac patients, arterial, mixed venous, and hepato-venous blood samples were taken synchronously after induction of anaesthesia (preCPB), during CPB, and 2 and 7 h after admission to the intensive care unit (ICU+2, ICU+7). Blood gas analysis, cardiac output, and hepato-splanchnic blood flow were measured. Free energy change gradients between mixed venous and arterial (-deltadeltaG(v - a)) and hepato-venous and arterial (-deltadeltaG(hv - a)) compartments were calculated. MEASUREMENTS AND RESULTS: Cardiac index (CI) increased from 1.9 (0.7) to 2.8 (1.3) L/min/m (median, inter-quartile range) (p = 0.001), and hepato-splanchnic blood flow index (HBFI) from 0.6 (0.22) to 0.8 (0.53) L/min/m (p = 0.001). Despite increasing flow, systemic oxygen extraction increased after CPB from 24 (10)% to 35 (10)% at ICU+2 (p = 0.002), and splanchnic oxygen extraction increased during CPB from 37 (19)% to 52 (14)% (p = 0.001), and remained high thereafter. After CPB, high splanchnic and systemic gradients of free energy change gradients were associated with high splanchnic and systemic oxygen extraction, respectively (p = 0.001, 0.033, respectively). CONCLUSION: Gradients of free energy change may be helpful in characterising adequacy of perfusion in cardiac surgery patients independently from measurements or calculations of data from oxygen transport.

Benefits of cardiac surgery in octogenarians--a postoperative quality of life assessment

OBJECTIVE: Assessment of postoperative quality of life in patients over 80 years after cardiac surgery including coronary artery bypass grafting (CABG), aortic valve replacement (AVR) and combined procedures. METHODS: Quality of life of n=136 patients over 80 years at operation (82.3+/-2.1 years), undergoing isolated CABG in 61 patients (45%), isolated AVR in 34 patients (25%) and a combination of CABG and AVR in 41 patients (30%) between January 1999 and December 2003 was reviewed. Preoperatively 66.2% presented in NYHA-class III/IV or CCS-class III/IV. Mean ejection fraction (EF) was 59.5%+/-14.0 (range 25-90%). Quality of life assessment was performed via a Seattle Angina Questionnaire. Follow-up was 100% complete for a total of 890 days (69-1853 days). RESULTS: Five-year survival was 70% for the CABG group, 75% for the AVR group and 65% for the CABG/AVR group. Quality of life was remarkable in all of the three groups after surgery. Overall 97 patients (81%) were not or little disabled in their daily activity. One hundred and twelve patients (93%) were free or considerably less symptomatic. Seventy-eight patients or 65% reported to be very satisfied with their current quality of life and 112 patients (93%) felt very reassured to have continuous full access to medical treatment despite of their advanced age. CONCLUSIONS: A remarkable quality of life and important improvement in the functional status after cardiac surgery in patients over 80 paired with a satisfactory medium-term survival justify early intervention for heart disease in this age group. Therefore, referral practice for patients over 80 years for heart surgery should be handled liberally.

[Wall calcifications of the left heart atrium]

The chest X-ray of a 61-year-old man with severe aortic and mitral stenosis revealed extensive, circularly arranged calcifications in the wall of the left atrial appendage. He died soon after admission to hospital and autopsy confirmed the atrial calcifications in association with severe mitral stenosis. Although such calcification of the left atrial wall is rare, it can be of importance because it may make the usual surgical approach to mitral valve replacement impossible.

The Ross procedure in infants and young children

BACKGROUND: This study reviews our experience with the Ross procedure in infants and young children. METHODS: From September 1993 to September 2004, 52 children less than 15 years of age underwent a Ross procedure. The patients ranged in age from 4 days to 15 years old (median, 5 years). Fifteen patients (29%) were less than 2 years of age. The predominant indication for the Ross procedure was aortic stenosis. Sixteen patients underwent a Ross-Konno procedure for severe left ventricular outflow tract obstruction. Thirty-four patients had 48 previous interventions. Preoperatively, 6 patients showed severe left ventricular dysfunction, and 2 of the patients required ventilation and inotropic support. Concomitant procedures were performed in 8 patients. Three patients had a mitral valve replacement, 2 patients had a ventricular septal defect closure and an aortic arch reconstruction, 2 patients had aortic arch reconstructions, and 1 patient had resection of a coarctation and a ventricular septal defect closure. RESULTS: Patients were followed up for a median of 43 months (range, 1 to 130). Overall survival was 85% +/- 5% at 1 and 82% +/- 5% at 2, 5, and 10 years. Hospital mortality was 5 of 52 patients (9.6%). All deaths occurred in neonates or infants less than 2 months of age, who needed urgent surgery. Three patients died late of noncardiac causes. At last follow-up, all patients were classified in New York Heart Association functional class I or II. No patient had endocarditis of the autograft or the right ventricular outflow tract replacement. During the follow-up, no event of thrombembolism was observed. No patient required the insertion of a permanent pacemaker. Overall freedom from reoperation is 57% +/- 15% at 10 years. One patient required the replacement of the autograft at 6 months postoperatively. The development of mild aortic insufficiency was observed in 24 patients, and moderate aortic insufficiency in 1 patient during follow-up. Freedom from reoperation for the right ventricular outflow tract replacement is 60% +/- 15% at 10 years. CONCLUSIONS: The Ross procedure represents an attractive approach to aortic valve disease in young children. However, a high early mortality rate has to be considered when performing this procedure in neonates or infants who present in critical preoperative condition.

Massive intraoperative thrombus of the aortic arch and proximal descending aorta

A 49-year-old male patient presented with a paravalvular leakage 18 years after aortic valve replacement. The patient received a mechanical valve and was weaned uneventfully from cardiopulmonary bypass. After a drop in the pressure curve of the left radial artery an additional line was placed in the proximal ascending aorta showing normal systemic pressure. Transesophageal echocardiography showed a massive circular thrombosis of the distal aortic arch. The patient received a covered stent to expand the residual aortic lumen and left the hospital in good health.

Severe aortic stenosis and coronary artery disease

Coronary artery disease (CAD) and aortic stenosis (AS) share pathophysiological mechanisms and risk factors. Moreover, the prevalence of CAD increases among elderly patients with severe AS since disease progression is strongly associated with age for both CAD and AS. These factors contribute to the frequent coexistence of CAD and AS. Patients with concomitant AS and CAD are characterised by higher baseline risk profiles with a larger number of comorbidities as compared to patients with isolated AS. Therefore, adequate therapeutic strategies are crucial for the treatment of these patients. The number of patients undergoing concomitant coronary artery bypass grafting (CABG) and surgical aortic valve replacement (SAVR) doubled during the last decade. Moreover, the development and rapid integration of transcatheter aortic valve implantation (TAVI) into clinical practice in western European countries has further extended invasive treatment of AS to elderly high-risk patients not considered suitable candidates for SAVR, frequently presenting with CAD. The aim of this review article is to provide an overview on CAD prevalence, impact on clinical outcomes, and treatment strategies in patients with severe AS requiring SAVR or TAVI.

Predictors of Permanent Pacemaker Implantation in Patients With Severe Aortic Stenosis Undergoing TAVR

Background Atrioventricular (AV) conduction disturbances requiring permanent pacemaker (PPM) implantation may complicate transcatheter aortic valve replacement (TAVR). Available evidence on predictors of PPM is sparse and derived from small studies. Objectives The objective of this study was to provide summary effect estimates for clinically useful predictors of PPM implantation after TAVR. Methods We performed a systematic search for studies that reported the incidence of PPM implantation after TAVR and that provided raw data for the predictors of interest. Data on study, patient, and procedural characteristics were abstracted. Crude risk ratios (RRs) and 95% confidence intervals for each predictor were calculated by use of random effects models. Stratified analyses by type of implanted valve were performed. Results We obtained data from 41 studies that included 11,210 TAVR patients, of whom 17% required PPM implantation after intervention. The rate of PPM ranged from 2% to 51% in individual studies (with a median of 28% for the Medtronic CoreValve Revalving System [MCRS] and 6% for the Edwards SAPIEN valve [ESV]). The summary estimates indicated increased risk of PPM after TAVR for men (RR: 1.23; p < 0.01); for patients with first-degree AV block (RR: 1.52; p < 0.01), left anterior hemiblock (RR: 1.62; p < 0.01), or right bundle branch block (RR: 2.89; p < 0.01) at baseline; and for patients with intraprocedural AV block (RR: 3.49; p < 0.01). These variables remained significant predictors when only patients treated with the MCRS bioprosthesis were considered. The data for ESV were limited. Unadjusted estimates indicated a 2.5-fold higher risk for PPM implantation for patients who received the MCRS than for those who received the ESV. Conclusions Male sex, baseline conduction disturbances, and intraprocedural AV block emerged as predictors of PPM implantation after TAVR. This study provides useful tools to identify high-risk patients and to guide clinical decision making before and after intervention.

Long-term outcome of elderly patients with severe aortic stenosis as a function of treatment modality

OBJECTIVE To assess long-term clinical outcomes of consecutive high-risk patients with severe aortic stenosis according to treatment allocation to transcatheter aortic valve implantation (TAVI), surgical aortic valve replacement (SAVR) or medical treatment (MT). METHODS Patients with severe aortic stenosis were consecutively enrolled into a prospective single centre registry. RESULTS Among 442 patients (median age 83 years, median STS-score 4.7) allocated to MT (n=78), SAVR (n=107), or TAVI (n=257) all-cause mortality amounted to 81%, 37% and 43% after a median duration of follow-up of 3.9 years (p<0.001). Rates of major adverse cerebro-cardiovascular events were lower in patients undergoing SAVR or TAVI as compared with MT (SAVR vs MT: HR 0.31, 95% CI 0.21 to 0.46) (TAVI vs MT: HR 0.34, 95% CI 0.25 to 0.46), with no significant difference between SAVR and TAVI (HR 0.88, 95% CI 0.62 to 1.25). Whereas SAVR (HR 0.39, 95% CI 0.24 to 0.61), TAVI (HR 0.37, 95% CI 0.26 to 0.52), and female gender (HR 0.72, 95% CI 0.53 to 0.99) were associated with improved survival, body mass index ≤20 kg/m(2) (HR 1.60, 95% CI 1.04 to 2.47), diabetes (HR 1.48, 95% CI 1.03 to 2.12), peripheral vascular disease (HR 2.01, 95% CI 1.44 to 2.81), atrial fibrillation (HR 1.74, 95% CI 1.28 to 2.37) and pulmonary hypertension (HR 1.43, 95% CI 1.03 to 2.00) were identified as independent predictors of mortality. CONCLUSIONS Among high-risk patients with severe aortic stenosis, long-term clinical outcome through 5 years was comparable between patients allocated to SAVR or TAVI. In contrast, patients with MT had a dismal prognosis.

Coronary revascularization and TAVI: before, during, after or never?

Aortic valve stenosis and coronary artery disease (CAD) frequently coexist in elderly patients selected for transcatheter aortic valve implantation (TAVI). Therapeutic strategies to manage concomitant obstructive CAD are therefore an important consideration in the overall management of patients with severe aortic stenosis (AS) undergoing TAVI. Conventional surgical aortic valve replacement and coronary artery bypass grafting is the treatment of choice for low and intermediate risk patients with symptomatic severe AS and concomitant obstructive CAD. However, TAVI and percutaneous coronary intervention (PCI) are viable alternative options for high-risk or inoperable patients presenting with symptomatic severe AS. PCI has been shown to be feasible and safe in selected high-risk or inoperable patients with symptomatic severe AS. However, the optimal timing of PCI relative to the TAVI procedure has been a subject of debate. The most frequent approch is staged PCI typically performed a few weeks prior to TAVI. However, concomitant PCI has also been shown to be a feasible and safe approach, particularly in patients with a low level of CAD complexity and an absence of severe renal impairment. Conversely, staged PCI should be considered in patients with higher degrees of CAD complexity, particularly in the presence of severe renal impairment. The aim of the present review is to discuss the safety and feasibility of performing PCI in elderly patients with severe AS and the optimal timing of PCI relative to the TAVI procedure using the most up-to-date available evidence.

Coronary artery disease in patients undergoing TAVI: why, what, when and how to treat.

Coronary artery disease (CAD) and aortic valve stenosis (AS) are frequently coexisting. It has been reported that CAD is present in 40% of patients with AS undergoing surgical aortic valve replacement, and in up to 60% of patients with AS undergoing transcatheter aortic valve implantation (TAVI). Elderly patients with CAD and AS are characterised by higher baseline risk profiles as compared to patients with isolated AS, increasing the complexity of their therapeutic management. In patients with CAD and AS the combination of coronary artery bypass grafting (CABG) and surgical aortic valve replacement has been shown to improve survival. Therefore, CABG is recommended in patients with CAD and AS undergoing surgical aortic valve replacement according to current guidelines of the European Society of Cardiology (ESC) and of the American College of Cardiology Foundation/American Heart Association (ACCF/AHA). Conversely, whether the presence of CAD has any prognostic implications in elderly patients with severe AS undergoing TAVI is still a matter of debate. Of note, according to the most recent ESC guidelines on myocardial revascularisation, percutaneous revascularisation should be considered in patients undergoing TAVI with a stenosis >70% in proximal coronary segments (class IIa, level of evidence C). The aim of this article is to provide an overview of evidence supporting the need for coronary revascularisation in patients with severe AS and CAD undergoing TAVI, and to summarise optimal timing and treatment modalities for percutaneous coronary interventions in these patients.

Assessment of low-flow, low-gradient, severe aortic stenosis: an invasive evaluation is required for decision making.

Low-flow, low-gradient severe aortic stenosis (AS) is characterised by a small aortic valve area (AVA) and low mean gradient (MG) secondary to a low cardiac output and may occur in patients with either a preserved or reduced left ventricular ejection fraction (LVEF). Symptomatic patients presenting with low-flow, low-gradient severe AS have a dismal prognosis independent of baseline LVEF if managed conservatively and should therefore undergo aortic valve replacement if feasible. Transthoracic echocardiography (TTE) is the first-line investigation for the assessment of AS haemodynamic severity. However, when confronted with guideline-discordant AVA (small) and MG (low) values, there are several reasons other than severe AS combined with a low cardiac output which may lead to such a situation, including erroneous measurements, small body size, inherent inconsistencies in the guidelines' criteria, prolonged ejection time and aortic pseudostenosis. The distinction between these various entities poses a diagnostic challenge. However, it is important to make a distinction because each has very different implications in terms of risk stratification and therapeutic management. In such instances, cardiac catheterisation forms an integral part of the work-up of these patients in order to confirm or refute the echocardiographic findings to guide management decisions appropriately.

Preinterventional screening of the TAVI patient: how to choose the suitable patient and the best procedure.

Transcatheter aortic valve implantation (TAVI) is a novel therapy, which has transformed the management of inoperable patients presenting with symptomatic severe aortic stenosis (AS). It is also a proven and less invasive alternative therapeutic option for high-risk symptomatic patients presenting with severe AS who are otherwise eligible for surgical aortic valve replacement. Patient age is not strictly a limitation for TAVI but since this procedure is currently restricted to high-risk and inoperable patients, it follows that most patients selected for TAVI are at an advanced age. Patient frailty and co-morbidities need to be assessed and a clinical judgment made on whether the patient will gain a measureable improvement in their quality of life. Risk stratification has assumed a central role in selecting suitable patients and surgical risk algorithms have proven helpful in this regard. However, limitations exist with these risk models, which must be understood in the context of TAVI. When making final treatment decisions, it is essential that a collaborative multidisciplinary "heart team" be involved and this is stressed in the most recent guidelines of the European Society of Cardiology. Choosing the best procedure is contingent upon anatomical feasibility, and multimodality imaging has emerged as an integral component of the pre-interventional screening process in this regard. The transfemoral route is now considered the default approach although vascular complications remain a concern. A minimal vessel diameter of 6 mm is required for currently commercial available vascular introducer sheaths. Several alternative access routes are available to choose from when confronted with difficult iliofemoral anatomy such as severe peripheral vascular disease or diffuse circumferential vessel calcification. The degree of aortic valve leaflet and annular calcification also needs to be assessed as the latter is a risk factor for post-procedural paravalvular aortic regurgitation. The ultimate goal of patient selection is to achieve the highest procedural success rate while minimizing complications and to choose patients most likely to derive tangible benefit from this procedure.

Novel emboli protection system during cardiac surgery: a multi-center, randomized, clinical trial.

BACKGROUND Stroke is a major cause of morbidity and mortality during open-heart surgery. Up to 60% of intraoperative cerebral events are emboli induced. This randomized, controlled, multicenter trial is the first human study evaluating the safety and efficacy of a novel aortic cannula producing simultaneous forward flow and backward suction for extracting solid and gaseous emboli from the ascending aorta and aortic arch upon their intraoperative release. METHODS Sixty-six patients (25 females; 68±10 years) undergoing elective aortic valve replacement surgery, with or without coronary artery bypass graft surgery, were randomized to the use of the CardioGard (CardioGard Medical, Or-Yehuda, Israel) Emboli Protection cannula ("treatment") or a standard ("control") aortic cannula. The primary endpoint was the volume of new brain lesions measured by diffusion-weighted magnetic resonance imaging (DW-MRI), performed preoperatively and postoperatively. Device safety was investigated by comparisons of complications rate, namely neurologic events, stroke, renal insufficiency and death. RESULTS Of 66 patients (34 in the treatment group), 51 completed the presurgery and postsurgery MRI (27 in the treatment group). The volume of new brain lesion for the treatment group was (mean±standard error of the mean) 44.00±64.00 versus 126.56±28.74 mm3 in the control group (p=0.004). Of the treatment group, 41% demonstrated new postoperative lesions versus 66% in the control group (p=0.03). The complication rate was comparable in both groups. CONCLUSIONS The CardioGard cannula is safe and efficient in use during open-heart surgery. Efficacy was demonstrated by the removal of a substantial amount of emboli, a significant reduction in the volume of new brain lesions, and the percentage of patients experiencing new brain lesions.

Clinical performance of a sutureless aortic bioprosthesis: five-year results of the 3f Enable long-term follow-up study.

OBJECTIVE Sutureless valves are designed to facilitate surgical implantation, including less-invasive techniques in aortic valve replacement, by maintaining surgical precision of implantation compared with transcatheter techniques. Long-term clinical experience with sutureless valves is lacking. We report the 5-year follow-up results of an international, prospective, multicenter study evaluating the clinical performance and safety of the 3f Enable valve (Medtronic Inc, Minneapolis, Minn). METHODS Between March 2007 and December 2009, 141 patients (54 male; mean age, 76.1±5.7 years) undergoing aortic valve replacement with the 3f Enable valve were enrolled in 10 European sites. The mean follow-up was 2.76 years (range, 2 days to 5.1 years; total, 388.7 patient-years). Echocardiographic valvular hemodynamic and morphologic analyses were performed by an independent core laboratory. RESULTS The mean systolic gradient was 10.4±4.4 mm Hg at discharge and 7.7±4.1 mm Hg at 5 years. The mean effective orifice area was 1.7±0.5 cm2 at discharge and 1.6±0.2 cm2 at 5 years. Freedom from all-cause and valve-related mortality was 87.6%±2.9% and 96.8%±1.6% at 1 year (113 patients at risk) and 77.0%±7.5% and 93.8%±4.8% at 5 years (24 patients at risk), respectively. Six patients underwent reoperation (4 because of major paravalvular leakage and 2 because of endocarditis). Freedom from reoperation was 95.4%±1.9% at 1 year and 95.4%±6.1% at 5 years. No structural valve deterioration occurred during the follow-up period. CONCLUSIONS The sutureless 3f Enable valve represents a safe and effective treatment for aortic valve stenosis, providing an excellent hemodynamic profile. This study represents the longest follow-up study for a sutureless bioprosthesis. Sutureless valves may become an option for all patients with indicated biological aortic valve replacement.

Komplikationen beim kathetergestützten Aortenklappenersatz nach transfemoralem Zugang

Hintergund Seit mehr als 10 Jahren wird der kathetergestützte Aortenklappenersatz (Transkatheter-Aortenklappenimplantation, „transcatheter aortic valve implantation“, TAVI) durchgeführt. Bereits in der Anfangsphase haben sich eingriffstypische Komplikationen nach transfemoralem Zugang herauskristallisiert. Ziel der Arbeit Beispielhaft wird anhand von 4 Sektionsfällen beschrieben, wie die Indikationsstellung zur TAVI und die Vermeidbarkeit der Komplikation zu prüfen ist. Material und Methoden Bei einer 86-jährigen Frau war es im Rahmen eines Repositionsversuchs des Implantats zu einem Abriss der rechten Beckengefäße gekommen. Bei einer 82-jährigen Frau war es während der Intervention zu einem Einriss des Aortenklappenrings mit Perikardtamponade gekommen. Eine 89-jährige Frau erlitt während der Intervention eine gedeckte Aortenverletzung und war während der anschließenden operativen Versorgung des Defekts verstorben. Im vierten Fall war bei einer 83 Jahre alt gewordenen Patientin im Rahmen des transfemoralen Klappenersatzes die Positionierung der Klappe misslungen, und ventrikelwärts entwickelte sich eine Embolisation der entfalteten Klappe. Es wurde eine zweite gleichartige Klappe positioniert, die in der Aorta hielt. Ergebnisse Die Indikationsstellung zur TAVI war in den 4 Fällen der multimorbiden Patientinnen gerechtfertigt. Die Komplikationen waren sehr unterschiedlich und die Gefäßverletzungen in 2 Fällen aufgrund der begonnenen Operationen nicht mehr zu prüfen. Schlussfolgerungen Die Versorgung einer Komplikation ist beim indikationsgerechten Patientenkollektiv aufgrund der Multimorbidität extrem schwierig und mit zahlreichen weiteren Komplikationen behaftet. Schlüsselwörter Herzklappenerkrankungen – Herzklappenprothese – Minimalinvasive Verfahren – Behandlungsfehler – Inoperabilität