Diastolic Filling Reserve Preservation Using a Semispherical Dacron Patch for Repair of Anteroapical Left Ventricular Aneurysm.

In postinfarction left ventricular aneurysm, abnormal geometry and desynchronized wall motion may cause a highly inefficient pump function. The traditional endoventricular patch plasty according to the Dor technique might result in a truncated and restrictive left ventricular cavity in small adults. We report a modified technique of left ventricular anteroapical aneurysm repair by using a semispherical reshaping patch to restore the left ventricular geometry.

Full-root aortic valve replacement with stentless xenograft achieves superior regression of left ventricular hypertrophy compared to pericardial stented aortic valves.

BACKGROUND: Full-root aortic valve replacement with stentless xenografts has potentially superior hemodynamic performance compared to stented valves. However, a number of cardiac surgeons are reluctant to transform a classical stented aortic valve replacement into a technically more demanding full-root stentless aortic valve replacement. Here we describe our technique of full-root stentless aortic xenograft implantation and compare the early clinical and midterm hemodynamic outcomes to those after aortic valve replacement with stented valves. METHODS: We retrospectively compared the pre-operative characteristics of 180 consecutive patients who underwent full-root replacement with stentless aortic xenografts with those of 80 patients undergoing aortic valve replacement with stented valves. In subgroups presenting with aortic stenosis, we further analyzed the intra-operative data, early postoperative outcomes and mid-term regression of left ventricular mass index. RESULTS: Patients in the stentless group were younger (62.6 ± 13 vs. 70.3 ± 11.8 years, p < 0.0001) but had a higher Euroscore (9.14 ± 3.39 vs.6.83 ± 2.54, p < 0.0001) than those in the stented group. In the subgroups operated for aortic stenosis, the ischemic (84.3 ± 9.8 vs. 62.3 ± 9.4 min, p < 0.0001) and operative times (246.3 ± 53.6 vs. 191.7 ± 53.2 min, p < 0.0001) were longer for stentless versus stented valve implantation. Nevertheless, early mortality (0% vs. 3%, p < 0.25), re-exploration for bleeding (0% vs. 3%, p < 0.25) and stroke (1.8% vs. 3%, p < 0.77) did not differ between stentless and stented groups. One year after the operation, the mean transvalvular gradient was lower in the stentless versus stented group (5.8 ± 2.9 vs. 13.9 ± 5.3 mmHg, p < 0.0001), associated with a significant regression of the left ventricular mass index in the stentless (p < 0.0001) but not in the stented group (p = 0.2). CONCLUSION: Our data support that full-root stentless aortic valve replacement can be performed without adversely affecting the early morbidity or mortality in patients operated on for aortic valve stenosis provided that the coronary ostia are not heavily calcified. The additional time necessary for the full-root stentless compared to the classical stented aortic valve replacement is therefore not detrimental to the early clinical outcomes and is largely rewarded in patients with aortic stenosis by lower transvalvular gradients at mid-term and a better regression of their left ventricular mass index.

Multikinase inhibitor sorafenib prevents pressure overload-induced left ventricular hypertrophy in rats by blocking the c-Raf/ERK1/2 signaling pathway.

BACKGROUND: Left ventricular hypertrophy (LVH) is a potent risk factor for sudden death and congestive heart failure. METHODS: We tested the effect of sorafenib, a multikinase inhibitor (10 mg/kg, given orally, starting 2 days prior to banding, till sacrifice on day 14), on the development of LVH following aortic banding in rats. RESULTS: The latter resulted in significant LVH caused by both an increase in cardiomyocyte volume and interstitial collagen deposition. The observed LVH was entirely blocked by sorafenib downregulating both of these components. LVH was associated with PDGF-BB and TGFß1 overexpression, as well as phosphorylation of c-raf and ERK1/2. Additionally, the transcription factors c-myc and c-fos leading to proliferation as well as the hypertrophy-inducing transcription factor GATA4 and its regulated gene ANP were all upregulated in response to aortic banding. All these overexpressions and upregulations were inhibited upon sorafenib treatment. CONCLUSION: We show that sorafenib exhibits a regulatory role on the occurrence of LVH following AB in rats by blocking the rise in growth factors PDGF-BB and TGFß1, activation of the corresponding c-Raf-ERK1/2 signaling pathway and effector mechanisms, including GATA4 and ANP. This effect of sorafenib may be of clinical importance in modulating the maladaptive hypertrophic response to pressure overload.

The development of cardiac surgery in an emerging country: a completed project.

The necessity to develop cardiac surgery centers in the emerging world is widely accepted. Numerous groups and organizations from the developed world are involved in such work; however, the best method in which to develop a sustainable center in the emerging world is still debated. Herein, we present an approach that we have used in several such projects, which involves regular and frequent instructional visits with progressive reduction of our instructional support. Data to support our approach are presented.

Introduction of an OPCAB program aimed at total arterial grafting in a multidisciplinary setting: feasible and safe?

BACKGROUND: The feasibility and the results of the introduction of an off-pump coronary artery bypass (OPCAB) program aimed at total arterial revascularization in a multidisciplinary institution were analyzed. Uniform surgical and anesthetic protocols were established and applied throughout the study period. METHODS: From March 2003--when the first OPCAB procedure of the program was performed--to July 2004, the data related to all the coronary artery bypass grafting procedures (N = 408) were prospectively recorded. The program was divided into two stages: the purpose of the first stage was to perform OPCAB in more than 90% of the patients, and that of the second stage was to proceed toward total arterial revascularization. The patients were grouped into four periods (102 patients for each period). Comparisons were performed with analysis of variance test and chi-square test where appropriate. RESULTS: For periods 1 to 4, the number of OPCAB procedures was 65/102 (64%), 82/102 (80%), 97/102 (95%), and 99/102 (97%), respectively (p < 0.001). The number of conversions did not vary significantly throughout the study (overall: 7/408, 1.7%), neither did the number of bypass/patient (overall: 3.05 +/- 0.86). The number of arterial graft/patient was 1.03 +/- 0.64, 1.01 +/- 0.4, 1.29 +/- 0.64, and 2.56 +/- 1, respectively (p < 0.001). During the last period, 81% (253/312) of the grafts were arterial. Overall mortality was 4.6% (19/408). For the OPCAB group, mortality was 2.9% (10/343) and perioperative myocardial infarction rate was 1.5% (5/343) with no statistically significant difference between the periods. CONCLUSIONS: With predefined standardized and coordinated protocols, an OPCAB program aimed at total arterial revascularization can be implemented rapidly and safely in a multidisciplinary setting.

Drug immunosuppression therapy for adult heart transplantation. Part 1: immune response to allograft and mechanism of action of immunosuppressants.

In the early days of transplantation, immunosuppression therapy was rather broad and nonspecific, mainly using high-dose corticosteroids and azathioprine. Thereafter we progressively narrowed the target of immunosuppressive strategy starting with polyclonal antibodies. The introduction of cyclosporine, OKT3, and tacrolimus further narrowed the target on the T-cell pathways. More recently mycophenolate mofetil progressively took the place of azathioprine with its higher lymphocyte specificity and sirolimus and interleukin-2 receptor antibodies were introduced. In this field in constant movement the aim is to find a drug or a regimen that provides optimal immunosuppression therapy with minimal side effects, in other words to find the right balance between overimmunosuppression and underimmunosuppression therapy. This review is divided into two parts. The first part will provide a basic understanding of the immunologic response to allograft and explain how conventional and recently introduced immunosuppressive agents work. The second part will describe the clinical application of immunosuppressive drugs to provide practical information for those in charge of heart transplant recipients.

Drug immunosuppression therapy for adult heart transplantation. Part 2: clinical applications and results.

This review describes the clinical application of classical immunosuppressive drugs as well as that of more recent drugs. All current immunosuppressive drugs target T-cell activation, and cytokine production and clonal expansion, or both. Immunosuppressive protocols can be broadly divided into induction therapy, maintenance immunosuppression, and treatment of acute rejection episodes.

High prevalence of unsuspected abdominal aortic aneurysms in patients hospitalised for surgical coronary revascularisation.

OBJECTIVES: Prevalence of abdominal aortic aneurysms (AAA) is not exactly known among patients with coronary artery disease (CAD) who are considered for surgical revascularisation. We evaluated the value of screening AAA among coronary patients admitted in our cardiovascular surgery unit. METHODS: Over a 24-month period, an abdominal echography was proposed to male patients aged 60 or more while hospitalised for surgical coronary revascularisation. Patients with previous investigation of the aorta were excluded. The aorta was considered aneurysmal when the anterior-posterior diameter was of 30 mm or more. RESULTS: Three hundred and ninety-five consecutive patients all accepted a proposed abdominal echographic screening for AAA. Forty unsuspected AAA were detected (10.1%). The mean diameter was 38.9 +/- 1.3 mm. Four AAA were larger than 50 mm and considered for surgery after the CABG procedure. Surveillance was proposed to the other 36, especially the 10 patients with an AAA larger than 40 mm. Patients with AAA were significantly older than those without AAA (71.3 +/- 0.8 vs. 69.4 +/- 0.3 years, P<0.05). Smoking history (P<0.05) and hypertension (P<0.05) were also associated more frequently with AAA. More than 16% of the patients being smokers and suffering hypertension presented with unsuspected AAA. CONCLUSIONS: In-hospital screening of AAA is very efficient among patients with coronary artery disease. Therefore, patients with CAD may be considered for routine AAA screening.

A new equine pericardial stentless valve.

OBJECTIVE: Small aortic valve replacement remains a challenging hemodynamic problem. A new bioprosthesis (3F Therapeutics, Lake Forest, Calif) was designed to further improve the hemodynamic performance currently achieved with stentless bioprostheses. This valve consists of a tubular structure assembled from 3 equal sections of equine pericardial material, with virtually no foreign material except for a thin polyester ring. Its hemodynamic performance was compared with that of a commercially available stentless prosthesis in a bovine model. PATIENTS AND METHODS: Twelve calves (55 +/- 2.8 kg) received a 19-mm 3F valve (3F group, n = 6) or a 19-mm stentless control valve (control group, n = 6). The animals were fully equipped for hemodynamic monitoring and transvalvular gradient measurements. After implantation, dopamine was infused in increasing doses, and the hemodynamic values were recorded at each step of 100-microg/min increase. Linear regression analysis was applied for group comparison of each variable. RESULTS: The mean transvalvular gradient at 4.5 L/min was 3.48 +/- 0.14 mm Hg (95% confidence interval) in the 3F group and 5.72 +/- 0.28 mm Hg in the control group (P <.0001) and at 6.5 L/min, 7.4 +/- 1.55 mm Hg, and 11.13 +/- 0.18 mm Hg, respectively (P <.0001). The effective orifice area at 4.5 L/min was 2.4 +/- 0.03 cm(2) in the 3F group and 1.86 +/- 0.02 cm(2) in the control group (P <.0001) and at 6.5 L/min, 2.41 +/- 0.04 cm(2), and 1.96 +/- 0.02 cm(2), respectively (P <.0001). CONCLUSIONS: This new bioprosthesis without a stent and without a supporting wall that has its commissures fixed directly to the aorta outperforms in vivo standard stentless prostheses in the immediate postimplant period.

In vivo testing of a right heart mini-pump during a 24 hour period: is it safe?

A coaxial atrial cannula connected to a mini-centrifugal pump was developed to bypass the right heart during extreme exposures in off-pump coronary artery bypass surgery. This study was designed to test the effect of this pump, running during 24 hours, on blood elements to evaluate its use as a prolonged right heart support. In a calf model (body weight 68+/-5 kg), the pump was inserted and set to its maximal motor speed of 7000 rpm. Blood samples were drawn every 6 hours for blood gas analyses, as well as for hematology and chemistry. The right heart mini-pump performed perfectly at its maximal speed over the 24 hour period. Blood gas parameters and blood lactate levels reflected adequate tissue perfusion (baseline: 2.2+/-0.5 mmol/L vs. 24 h: 2+/-0.3 mmol/L; p = 0.64). Red blood cell count was stable (baseline: 9.8+/-1.4 x 10(12)/L vs. 24 h: 9.6+/-1.1 x 10(12)/L; p = 0.83). Free plasma hemoglobin remained below 100 mg/L throughout the experiment. Platelet count was stable during the first 6 hours and exhibited a tendency to drop thereafter (baseline: 749+/-104 x 10(9)/L vs. 24 h: 486+/-20 x 10(9)/L; p = 0.01). This right heart mini-pump appears to provide sufficient blood flow during a 24 hour period with minimal impact on red cell and moderate platelet damage after 6 hours. These results suggest a potential application of this system for postcardiotomy right heart support.

A new expandable venous cannula for minimal access heart surgery.

BACKGROUND: During percutaneous cannulation, the diameter of the venous cannula is determined by the size of the access site. To limit this restriction, the Smart cannula (Cardiosmart Ltd., Fribourg, Switzerland) has been developed. Because its design allows self-expansion within the recipient vein, diameter restriction is limited to the access site. METHODS: In 6 calves (78 +/- 4.3 kg), the jugular vein and the carotid artery were cannulated through a cervicotomy. The Smart cannula was tested against three percutaneous cannulas with a diameter of 27, 25, and 21F, respectively. Stenotic percutaneous access to the vein was simulated by 1-cm wide tape encircling the vein that could be adjusted to a diameter of 27, 25, and 21F, respectively. The maximal flow rate, reached with stable reservoir level and a negative pressure of 44 mm Hg, was determined three times for each access size with the Smart cannula (one size fits all) and the corresponding percutaneous cannula successively. RESULTS: For an access size of 27F, the flow of the Smart cannula was 5.7 +/- 0.4 L/min and that of the percutaneous cannula was 4.3 +/- 0.2 L/min (p < 0.0001); for 25F, flow rates were 5.6 +/- 0.5 and 3.9 +/- 0.2 L/min, respectively (p < 0.0001); and for 21F, the flow rates were 4.3 +/- 0.4 and 2.7 +/- 0.3 L/min, respectively (p < 0.0001). The percentage increase of flow for the 27, 25, and 21F sizes were 34% +/- 9%, 42% +/- 16%, and 53% +/- 18%, respectively (one-way analysis of variance, p = 0.014). CONCLUSIONS: For the present set-up, the Smart cannula outperforms commercially available percutaneous cannulas. The smaller the size of the insertion site, we observed a higher gain of flow with the Smart cannula.

Circulatory support for OPCAB procedures.

During off-pump coronary artery bypass grafting (OPCAB) which allows complete revascularization through a median sternotomy, revascularization of the lateral and posterior walls requires the verticalization of the heart, which may cause haemodynamic disturbance. This concern has stimulated the development of circulatory support with mini-pumps. Initially, these pumps were designed for the right side of the heart, which was found to be the main contributor to haemodynamic instability under experimental conditions. The three types of mini-pumps that have been developed so far - two for the right side of the heart and one for both sides - are reviewed as well as a new concept of integrated cardiopulmonary bypass (CPB) circuit with reduced surface and priming volume. However, with increasing experience and improved methods of exposition, OPCAB has become a procedure that can be performed without support in the majority of the cases. Nevertheless, the concept of miniaturization and the possibility to insert these devices through a peripheral access has opened the way to new indications, mainly short-term circulatory support for acute heart failure. This development is welcome in a field where available devices are invasive and plagued with a heavy morbidity.

Hemodynamics optimization during off-pump coronary artery bypass: the 'no compression' technique.

OBJECTIVE: Heart manipulation during OPCAB may cause hemodynamical instability in particular for access to the posterior and lateral walls. The 'no compression' technique involves enucleation of the heart without any compression on the cavities, and stabilization of the target area with a suction device. The impact of this technique on hemodynamics is assessed. METHODS: In order to analyze a homogeneous group, 26 consecutive patients with triple grafts, one to each side of the heart in the same sequential order (posterior, lateral and anterior wall successively) were selected. Heart rate (HR), mean pulmonary arterial pressure (PAP, mmHg), pulmonary capillary wedge pressure (PCWP, mmHg), mean arterial pressure (MAP, mmHg), cardiac output index (COI, l/min per m(2)), and central venous saturation (SvO(2),%) were monitored. A coronary shunt was used for all the anastomoses. RESULTS: HR was stable with baseline value of 60+/-10 and the highest value for the anterior wall, 63.6+/-8 (P=0.23). PAP and PCWP exhibited their highest increase, when compared with baseline, for the lateral wall, 23.9+/-4.7 vs. 20.7+/-6.2 (P=0.06), and 17.2+/-4.7 vs. 14.9+/-5.6 (P=0.16), respectively. MAP, COI and SvO(2), exhibited their largest drop, when compared with baseline, for the lateral wall too, 73.1+/-9.1 vs. 77.1+/-7.5 (P=0.12), 1.99+/-0.47 vs. 2.26+/-0.55 (P=0.09), and 70.5+/-8.4 vs. 74.8+/-9.3 (P=0.12), respectively. CONCLUSIONS: None of the hemodynamical parameter differed significantly from baseline value for all three territories. While hemodynamics was perfectly maintained during the posterior and anterior walls revascularization, exposure of the lateral wall led to marginal changes only.

Atrial fibrillation and minimally invasive coronary artery bypass grafting: risk factor analysis.

Atrial fibrillation (AF) is a frequent arrhythmia after conventional coronary artery bypass grafting. With the advent of minimally invasive technique for left internal mammary artery-left anterior descending coronary artery (LIMA-LAD) grafting, we analyzed the incidence and the risk factors of postoperative AF in this patient population. This prospective study involves all patients undergoing isolated LIMA-LAD grafting with minimally invasive technique between January 1994 and June 2000. Twenty-four possible risk factors for postoperative AF were entered into univariate and multivariate logistic regression analyses. Postoperative AF occurred in 21 of the 90 patients (23.3%) analyzed. Double- or triple-vessel disease was present in 12/90 patients (13.3%). On univariate analysis, right coronary artery disease (p <0.01), age (p = 0.01), and diabetes (p = 0.04) were found to be risk factors for AF. On multivariate analysis, right coronary artery disease was identified as the sole significant risk factor (p = 0.02). In this patient population, the incidence of AF after minimally invasive coronary artery bypass is in the range of that reported for conventional coronary artery bypass grafting. Right coronary artery disease was found to be an independent predictor, and this may be related to the fact that in this patient population the diseased right coronary artery was not revascularized at the time of the surgical procedure. For the same reason, this risk factor may find a broader application to noncardiac thoracic surgery.

A new concept of integrated cardiopulmonary bypass circuit.

OBJECTIVE: Standard cardiopulmonary bypass (CPB) circuits with their large surface area and volume contribute to postoperative systemic inflammatory reaction and hemodilution. In order to minimize these problems a new approach has been developed resulting in a single disposable, compact arterio-venous loop, which has integral kinetic-assist pumping, oxygenating, air removal, and gross filtration capabilities (CardioVention Inc., Santa Clara, CA, USA). The impact of this system on gas exchange capacity, blood elements and hemolysis is compared to that of a conventional circuit in a model of prolonged perfusion. METHODS: Twelve calves (mean body weight: 72.2+/-3.7 kg) were placed on cardiopulmonary bypass for 6 h with a flow of 5 l/min, and randomly assigned to the CardioVention system (n=6) or a standard CPB circuit (n=6). A standard battery of blood samples was taken before bypass and throughout bypass. Analysis of variance was used for comparison. RESULTS: The hematocrit remained stable throughout the experiment in the CardioVention group, whereas it dropped in the standard group in the early phase of perfusion. When normalized for prebypass values, both profiles differed significantly (P<0.01). Both O2 and CO2 transfers were significantly improved in the CardioVention group (P=0.04 and P<0.001, respectively). There was a slightly higher pressure drop in the CardioVention group but no single value exceeded 112 mmHg. No hemolysis could be detected in either group with all free plasma Hb values below 15 mg/l. Thrombocyte count, when corrected by hematocrit and normalized by prebypass values, exhibited an increased drop in the standard group (P=0.03). CONCLUSION: The CardioVention system with its concept of limited priming volume and exposed foreign surface area, improves gas exchange probably because of the absence of detectable hemodilution, and appears to limit the decrease in the thrombocyte count which may be ascribed to the reduced surface. Despite the volume and surface constraints, no hemolysis could be detected throughout the 6 h full-flow perfusion period.

[ECMO and cardiopulmonary support]. / ECMO et support cardio-circulatoire.

ECMO (extracorporeal membrane oxygenation) may be viewed as a prolonged cardiopulmonary bypass allowing for a prolonged cardio-respiratory support. Since its introduction in the 60's, its indication has expanded from acute respiratory failure to acute cardiac failure refractory to conventional treatments. The target group involves mainly those patients presenting with a cardiogenic shock following cardiac surgery or acute myocardial infarction. The advantages of this form of circulatory support, when compared with long-term ventricular assist devices, are its less invasive aspect, its ease of implantation and its reduced cost. However, its main limitation lies in its limited duration of 7 to 10 days, in particular because of hemorrhage complications. Currently, ECMO provides a temporary hemodynamical stability in order to perform an invasive cardiac treatment (coronary bypass or percutaneous dilatation), or to assess the eligibility of the patient for a long-term ventricular assist device, which will enable to wait for the availability of an allograft. The latter scenario is crucial nowadays because of the severe lack of organ donors, which is the leading cause of death among patients waiting for a heart transplant.

[Long-term mechanical circulatory support for terminal cardiac insufficiency refractory to medical treatment]. / L'assistance circulatoire mécanique à long terme pour l'insuffisance cardiaque terminale réfractaire au traitement médical.

Constant progress has been made over the years in order to improve the performance of mechanical circulatory support devices. After the introduction of portable blood pump systems into clinical practice, we now study the performance characteristics of totally implantable mechanical circulatory support systems which do not require percutaneous drive lines or percutaneous electrical wiring. As a matter of fact, transcutaneous energy transfer is now achieved by induction, and pump controller performance read-out and pump parameter adjustment is performed by telemetry. The indication for clinical use of such devices has to be evaluated carefully. Mainly patients in need of a heart transplant but having contraindications to move forward (advanced age, former neoplasm, persistent antibodies) have benefits from such devices as destination therapy.

Success of thrombolysis as a predictor of outcome in acute thrombosis of popliteal aneurysms.

PURPOSE: Acute limb ischemia after thrombosis of a popliteal aneurysm is a distinct and limb-threatening entity. Preoperative intra-arterial thrombolysis may improve the outcome in this challenging situation. This study retrospectively analyzed a consecutive series of patients treated with preoperative thrombolysis and subsequent revascularization. METHODS: Thirteen patients with acute limb ischemia caused by thrombosis of a popliteal aneurysm underwent catheter-directed intra-arterial thrombolysis with urokinase and subsequent vascular reconstruction. The angiographic and clinical outcome was analyzed and compared with that in the literature. RESULTS: Complete aneurysm thrombosis with absence of runoff was documented in 12 cases. Thrombolysis restored perfusion with patency of the popliteal artery and a one- or two-vessel runoff in 77% of cases (10/13). Early cumulative graft patency and limb salvage rates were 68% and 83%, respectively, with an ankle/brachial index of 0.8 +/- 0.2. Lytic failure followed by attempts at bypass grafting was present in three patients (23%) and resulted in above-knee amputation. Severe rhabdomyolysis and fatal pulmonary embolism were responsible for a 15% early mortality rate. CONCLUSION: Preoperative thrombolysis followed by bypass grafting is a valid treatment option for patients who can withstand an additional period of ischemia that does not require immediate revascularization and intraoperative lysis. Lytic failure identifies patients with a highly compromised runoff who are probably best treated by means of subsequent amputation, without any attempts at bypass grafting.

Hemocompatibility of a coaxial pump catheter for less invasive heart surgery.

Off-pump coronary artery bypass (OPCAB) requires heart manipulation during exposure of the lateral and posterior walls of the heart, which may cause hemodynamic instability, mainly through right ventricular dysfunction. A coaxial atrial cannula connected to a minicentrifugal pump was developed to bypass the right heart. This study was designed to test the hemocompatibility of this pump ongoing for 6 h. In five calves (bodyweight, 70.3+/-4.2 kg), the pump was inserted and set to its maximal motor speed of 7000 rpm. Blood samples were taken for blood gas analyses, hematology and chemistry on an hourly basis. ANOVA was used for statistical analysis. During the 6-h run, hematocrit and red blood cell count were stable (p=0.77 and 0.87, respectively). Platelet count was not significantly altered (p=0.55). LDH was stable (p=0.61) and plasma free hemoglobin remained below 100 mg/l throughout the experiment. Adequate tissue perfusion was maintained as reflected by the stable mixed venous oxygen saturation (baseline, 72.5+/-2%, and 6 h, 65.6+/-3.4%) and no defect of any pump system was detected during this 6-h testing. This right heart minipump appears to have a minimal impact on red cells and platelets when set at its maximal speed for 6 h, underlining the hematological safety of the system.

Optimized venous return with a self-expanding cannula: from computational fluid dynamics to clinical application.

The Smart canula concept allows for collapsed cannula insertion, and self-expansion within a vein of the body. (A) Computational fluid dynamics, and (B) bovine experiments (76+/-3.8 kg) were performed for comparative analyses, prior to (C) the first clinical application. For an 18F access, a given flow of 4 l/min (A) resulted in a pressure drop of 49 mmHg for smart cannula versus 140 mmHg for control. The corresponding Reynolds numbers are 680 versus 1170, respectively. (B) For an access of 28F, the maximal flow for smart cannula was 5.8+/-0.5 l/min versus 4.0+/-0.1 l/min for standard (P<0.0001), for 24F 5.5+/-0.6 l/min versus 3.2+/-0.4 l/min (P<0.0001), and for 20F 4.1+/-0.3 l/min versus 1.6+/-0.3 l/min (P<0.0001). The flow obtained with the smart cannula was 270+/-45% (20F), 172+/-26% (24F), and 134+/-13% (28F) of standard (one-way ANOVA, P=0.014). (C) First clinical application (1.42 m2) with a smart cannula showed 3.55 l/min (100% predicted) without additional fluids. All three assessment steps confirm the superior performance of the smart cannula design.