Temporal trends in treatment and outcomes for advanced heart failure with reduced ejection fraction from 1993-2010: findings from a university referral center.

BACKGROUND: Randomized trials have demonstrated the efficacy of several new therapies for heart failure (HF) with reduced ejection fraction over the preceding 2 decades. This study investigates whether these therapeutic advances have translated into improvement in outcomes for patients with advanced HF referred to a heart transplant center. METHODS AND RESULTS: Patients with HF (n=2507) referred to a single university center were analyzed in three 6-year eras during which medical and device therapies were evolving: 1993 to 1998 (era 1), 1999 to 2004 (era 2), and 2005 to 2010 (era 3). Impaired hemodynamics and comorbidities were more frequent at time of referral in later eras, whereas other HF severity parameters where similar or improved. Successive eras had greater usage of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, ß-blockers, aldosterone antagonists, implantable cardioverter defibrillators, and cardiac resynchronization therapy, consistent with evolving evidence and guideline recommendations over the study period. All-cause mortality and sudden death were significantly lower in era 2 and 3 compared with era 1. After multivariable risk adjustment, era 3 had significantly decreased 2- and 3-year all-cause mortality risk and significantly decreased 1- and 3-year sudden death risk compared with era 1. However, progressive HF death and the combined outcome of mortality/urgent transplant/ventricular assist device were modestly increased in the latter eras. CONCLUSIONS: Over the past 2 decades, patients with advanced HF referred to and managed at a tertiary university referral center have benefited from advances in HF medications and devices, as evidenced by improvements in overall survival and sudden death risk.

A quantitative analysis of valgus torque on the ACL: a human cadaveric study.

The loads needed to elicit a positive pivot shift test in a knee with an anterior cruciate ligament (ACL) rupture have not been quantified. The coupled anterior tibial translation (ATT), coupled internal tibial rotation (ITR), and the in situ force in the ACL in response to a valgus torque, an inherent component of the pivot shift test, were measured in 10 human cadaveric knee specimens. Using a robotic/universal force-moment sensor testing system, valgus torques ranging from 0.0 to 10.0 Nm were applied in nine increments on the intact and ACL-deficient knee in flexion ranging from 0 degrees to 90 degrees. At 15 degrees of knee flexion, the coupled ATT and ITR were significantly increased in the ACL-deficient knee when compared to the intact knee. Coupled ATT increased a maximum of 291% (6.7 mm, p<0.05), while coupled ITR increased a maximum of 85% (5.1 degrees, p<0.05). At 30 degrees, the increases in coupled ATT and ITR were significant at valgus loads of 3.3 Nm and greater with a maximum increase in coupled ATT of 137% (6.3 mm, p<0.05) and a maximum increase in coupled ITR of 38% (3.6 degrees, p<0.05). At 45 degrees, coupled ATT increased significantly (maximum of 69%, 4.4 mm, p<0.05), but only at torques > or =6.7 Nm. The in situ force in the ACL was less than 20 N for all flexion angles when a torque between 3.3 and 5.0 Nm was applied. Low valgus torque elicited tibial subluxation in the ACL-deficient knee with low in situ ACL forces, similar to a positive pivot shift test. Thus, application of a valgus torque may be suitable to evaluate ACL-deficient and ACL-reconstructed knees, since subluxation can be achieved with minimal harm to the ACL graft. This work is important in understanding one load component needed for the pivot shift examination; further studies quantifying other load components are essential for better comprehension of the in vivo pivot shift examination.

Knee stability and graft function following anterior cruciate ligament reconstruction: Comparison between 11 o'clock and 10 o'clock femoral tunnel placement. 2002 Richard O'Connor Award paper.

PURPOSE: To study how well an anterior cruciate ligament (ACL) graft fixed at the 10 and 11 o'clock positions can restore knee function in response to both externally applied anterior tibial and combined rotatory loads by comparing the biomechanical results with each other and with the intact knee. TYPE OF STUDY: Biomechanical experiment using human cadaveric specimens. METHODS: Ten human cadaveric knees (age, 41+/-13 years) were reconstructed by placing a bone-patellar tendon-bone graft at the 10 and 11 o'clock positions, in a randomized order, and then tested using a robotic/universal force-moment sensor testing system. Two external loading conditions were applied: (1) 134 N anterior tibial load with the knee at full extension, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion, and (2) a combined rotatory load of 10 N-m valgus and 5 N-m internal tibial torque with the knee at 15 degrees and 30 degrees of flexion. The resulting kinematics of the reconstructed knee and in situ forces in the ACL graft were determined for each femoral tunnel position. RESULTS: In response to a 134-N anterior tibial load, anterior tibial translation (ATT) for both femoral tunnel positions was not significantly different from the intact knee except at 90 degrees of knee flexion as well as at 60 degrees of knee flexion for the 10 o'clock position. There was no significant difference in the ATT between the 10 and 11 o'clock positions, except at 90 degrees of knee flexion. Under a combined rotatory load, however, the coupled ATT for the 11 o'clock position was approximately 130% of that for the intact knee at 15 degrees and 30 degrees of flexion. For the 10 o'clock position, the coupled ATT was not significantly different from the intact knee at 15 degrees of flexion and approximately 120% of that for the intact knee at 30 degrees of flexion. Coupled ATT for the 10 o'clock position was significantly smaller than for the 11 o'clock position at 15 degrees and 30 degrees of flexion. The in situ force in the ACL graft was also significantly higher for the 10 o'clock position than the 11 o'clock position at 30 degrees of flexion in response to the same loading condition (70 +/- 18 N v 60 +/- 15 N, respectively). CONCLUSIONS: The 10 o'clock position more effectively resists rotatory loads when compared with the 11 o'clock position as evidenced by smaller ATT and higher in situ force in the graft. Despite the fact that ACL grafts placed at the 10 or 11 o'clock positions are equally effective under an anterior tibial load, neither femoral tunnel position was able to fully restore knee stability to the level of the intact knee.

The effect of soft-tissue graft fixation in anterior cruciate ligament reconstruction on graft-tunnel motion under anterior tibial loading.

PURPOSE: To compare the motion of an anterior cruciate ligament (ACL) replacement graft within the femoral bone tunnel (graft- tunnel motion) when a soft-tissue graft is secured either by a titanium button and polyester tape (EndoButton fixation; Acufex, Smith & Nephew, Mansfield, MA) or by a biodegradable interference screw (Biointerference fixation; Endo-fix; Acufex, Smith & Nephew) An additional purpose was to evaluate the effect of the graft-tunnel motion on the kinematics of ACL-reconstructed knees and in situ force of the ACL replacement graft. TYPE OF STUDY: Biomechanical experiment using an in vitro animal model. METHODS: ACL reconstruction with a flexor tendon autograft was performed in 8 cadaveric knees of skeletally mature goats. The knee kinematics and the in situ force in the ACL replacement graft in response to anterior tibial loads were evaluated using the robotic/universal force-moment sensor testing system. The longitudinal and transverse graft-tunnel motion during anterior tibial loading was determined based on radiographic measurements parallel and perpendicular to the femoral bone tunnel, respectively. RESULTS: In response to an anterior tibial load of 100 N, the longitudinal graft-tunnel motion for EndoButton fixation and Biointerference fixation was 0.8 +/- 0.4 mm and 0.2 +/- 0.1 mm, respectively (P <.05), whereas the transverse graft-tunnel motion was 0.5 +/- 0.2 mm and 0.1 +/- 0.1 mm, respectively (P <.05). Furthermore, the anterior tibial translation for EndoButton fixation (5.3 +/- 1.2 mm) was also significantly larger than that for Biointerference fixation (4.2 +/- 0.9 mm) (P <.05). With both fixations, however, no significant difference between the in situ forces in the ACL replacement graft and that in the intact ACL could be detected. CONCLUSIONS: EndoButton fixation of a soft-tissue graft via an elastic material resulted in significantly larger graft-tunnel motion, and consequently, greater anterior knee laxity compared with more rigid fixation using an interference screw closer to the intra-articular entrance of the bone tunnel. In terms of force distribution, the ACL replacement graft in both fixations still functioned as a primary restraint to an anterior tibial load close to the intact ACL.