Benjamin Medalion

Aortic valve replacement: Is valve size important?

OBJECTIVEnWe sought to determine whether aortic prosthesis size adversely influences survival after aortic valve replacement.nnnMETHODSnA total of 892 adults receiving a mechanical (n = 346), pericardial (n = 463), or allograft (n = 83) valve for aortic stenosis were observed for up to 20 years (mean, 5.0 +/- 3.9 years) after primary isolated aortic valve replacement. We used multivariable propensity scores to adjust for valve selection factors, multivariable hazard function analyses to identify risk factors for all-cause mortality, and bootstrap resampling to quantify the reliability of the results.nnnRESULTSnTwenty-five percent of patients had indexed internal orifice areas of less than 1.5 cm(2)/m(2) and more than 2 SDs (Z-value) below predicted normal aortic valve size. Mechanical valve orifices were smaller (1.3 +/- 0. 29 cm(2)/m(2), Z = -2.2 +/- 1.16) than pericardial (1.9 +/- 0.36 cm(2)/m(2), Z = -0.40 +/- 1.01) or allograft valves (2.1 +/- 0.50, Z = 0.24 +/- 1.17). The overall survival was 98%, 96%, 86%, 69%, and 49% at 30 days and 1, 5, 10, and 15 years postoperatively. Univariably, survival was weakly and inversely related to manufacturer valve size (P =.16) and internal orifice diameter (P =. 2) but completely unrelated to indexed valve area (P =.6) or Z-value (P =.8). These, and univariable differences among valve types (P =. 004), were accounted for by different prevalences in patient risk factors and not by valve size or type per se. Bootstrap resampling indicated that these findings had a less than 15% chance of being incorrect.nnnCONCLUSIONSnSurvival after aortic valve replacement is strongly related to patient risk factors but appears not to be adversely affected by moderate patient-prosthesis mismatch (down to about 4 SDs below normal). Aortic root enlargement to accommodate a large prosthesis may be required in few situations.

Assessment of sternal vascularity with single photon emission computed tomography after harvesting of the internal thoracic artery.

OBJECTIVEnThis study prospectively evaluates the effect on sternal vascularity of harvesting the left internal thoracic artery.nnnMETHODSnTwenty-four consecutive patients undergoing primary coronary artery bypass grafting were studied. One patients procedure was altered during the operation, and he was eliminated from the study. The patients were prospectively randomized to receive a skeletonized internal thoracic artery (group I, n = 11) or a pedicled internal thoracic artery (group II, n = 12) graft. Each patient underwent a preoperative technetium 99 methylene diphosphonate bone scan using single photon emission computed tomography. The ratio of the mean counts per pixel on the left side of the sternum was compared with the mean counts per pixel on the right side. Postoperatively, all patients had a second scan, and sternal uptake was compared with the preoperative uptake.nnnRESULTSnNo significant differences in preoperative and operative variables were observed between the groups. A statistically significant reduction in blood flow to the left side of the sternum was shown postoperatively in group II compared with group I (0.61 +/- 0.11 vs 0.85 +/- 0.09; P <.001). Multivariable logistic regression analysis of preoperative and operative variables revealed only a pedicled left internal thoracic artery to be associated with a 20% or more reduction in left-to-right sternal activity ratio (odds ratio, 100; 70% confidence limits, 22-465; P =.002).nnnCONCLUSIONnA pedicled left internal thoracic artery graft to the left anterior descending artery reduces blood flow to the left side of the sternum during the acute postoperative period. This does not occur when the left internal thoracic artery is skeletonized.

Aortic valve replacement for octogenarians: are small valves bad?

BACKGROUNDnAs the population ages, more octogenarians become candidates for aortic valve replacement. Many octogenarians, particularly women, have a small aortic annulus and there is uncertainty as to the optimal management of this situation in that age group.nnnMETHODnTo examine this issue, we reviewed 248 octogenarians (mean age, 82.6 +/- 2.3 years; 58% men) who underwent primary isolated aortic valve replacement (n = 99), or aortic valve replacement and coronary revascularization (n = 149), between 1980 and 1995. Nineteen-millimeter valves were used in 26% of the patients.nnnRESULTSnIn-hospital mortality was 8.9%, 5% for aortic valve replacement alone and 11.4% for aortic valve replacement and coronary revascularization. It was 12.5% for the 19-mm size valves compared with 7.7% for the bigger size valves (p = 0.24). Follow-up (mean interval, 4.4 years) demonstrated survival for all patients of 85%, 60%, and 30% and survival free from cardiovascular events of 80%, 45%, and 21% at 1, 5, and 10 postoperative years, respectively. Multivariate analysis identified triple-vessel disease and preoperative congestive heart failure as associated with increased risk for both in-hospital and late mortality (p < 0.05). Valve size did not influence late survival or event-free survival regardless of body surface area.nnnCONCLUSIONSnThe use of small aortic valve prostheses in octogenarians does not adversely affect the incidence of early or late mortality or cardiac events.

Endogenous Basic Fibroblast Growth Factor Displaced by Heparin From the Lumenal Surface of Human Blood Vessels Is Preferentially Sequestered by Injured Regions of the Vessel Wall

BACKGROUNDnProliferation of smooth muscle cells (SMCs) of the arterial wall in response to local injury is an important factor in vascular proliferative disorders. Among the growth factors that promote SMC proliferation is basic fibroblast growth factor (bFGF), which is characterized by a high affinity for heparin and is associated with heparan sulfate on cell surfaces and extracellular matrices. We investigated whether heparin can displace endogenous active bFGF from the lumenal surface of blood vessels, whether bFGF is preferentially bound to injured blood vessels, and whether a synthetic, polyanionic, heparin-mimicking compound (RG-13577) can prevent sequestration of bFGF by the vessel wall.nnnMETHODS AND RESULTSnInjured and noninjured saphenous vein segments were perfused with or without heparin, in the absence or presence of 125I-bFGF and/or RG-13577 (a polymer of 4-hydroxyphenoxy acetic acid). Heparin displaced bFGF from the lumenal surface of the vein, and the released bFGF stimulated proliferation of SMCs. Likewise, systemic administration of heparin during open heart surgery resulted in a marked increase in plasma bFGF levels. Injured veins sequestered 125I-bFGF to a much higher extent than noninjured vein segments, both in the absence and presence of heparin. This sequestration was inhibited by compound RG-13577.nnnCONCLUSIONSnDespite its beneficial effects, heparin may displace active bFGF, which subsequently may be preferentially deposited on injured vessel walls, thus contributing to the pathogenesis of restenosis. This effect may be prevented by a synthetic heparin-mimicking compound.

Extracorporeal life support in patients with multiple injuries and severe respiratory failure: a single-center experience?

BACKGROUND The use of extracorporeal life support in trauma casualties is limited by concerns regarding hemorrhage, particularly in the presence of traumatic brain injury (TBI). We report the use of extracorporeal membrane oxygenation (ECMO)/interventional lung assist (iLA) as salvage therapy in trauma patients. High-flow technique without anticoagulation was used in patients with coagulopathy or TBI. METHODS Data were collected from all adult trauma patients referred to one center for ECMO/iLA treatment owing to severe hypoxemic respiratory failure. RESULTS Ten casualties had a mean (SD) Injury Severity Score (ISS) of 50.3 (10.5) (mean [SD] age, 29.8 [7.7] years; 60% male) and were supported 9.5 (4.5) days on ECMO (n = 5) and 7.6 (6.5) days on iLA (n = 5). All experienced blunt injury with severe chest injuries, including one cardiac perforation. Most were coagulopathic before initiation of ECMO/iLA support. Among the seven patients with TBI, four had active intracranial hemorrhage. Complications directly related to support therapy were not lethal; these included hemorrhage from a cannulation site (n = 1), accidental removal of a cannula (n = 1), and pressure sores (n = 3). Deaths occurred owing to septic (n = 2) and cardiogenic shock (n = 1). Survival rates were 60% and 80% on ECMO and iLA, respectively. Follow-up of survivors detected no neurologic deterioration. CONCLUSION ECMO/iLA therapy can be used as a rescue therapy in adult trauma patients with severe hypoxemic respiratory failure, even in the presence of coagulopathy and/or brain injury. The benefits of rewarming, acid-base correction, oxygenation, and circulatory support must be weighed individually against the risk of hemorrhage. Further research should determine whether ECMO therapy also confers survival benefit. LEVEL OF EVIDENCE Therapeutic study, level V.

Similar incidence of hypotension with combined spinal-epidural or epidural alone for knee arthroplasty.

Objectif nNous avons emis ľhypothese que ľincidence ďhypotension pendant ľarthroplastie totale du genou (ATG) serait plus faible avec ľanesthesie rachidienne et peridurale combinee (RPC) qu’avec ľanesthesie peridurale seule.BackgroundWe hypothesized that the incidence of hypotension during total knee replacement (TKR) surgery is lower in patients given combined spinal-epidural (CSE) anesthesia vs those receiving epidural anesthesia alone.MethodsIn a prospective study, 80 American Society of Anesthesiologists I–II patients (aged 40–80 yr), undergoing elective TKR surgery were randomly assigned to either CSE anesthesia (CSE,n = 40) or epidural anesthesia alone (Epidural,n = 40). Hemodynamic measurements included oscillometric mean arterial blood pressure (MAP), heart rate (HR), and cardiac index (CI) as determined by thoracic bioimpedance; systemic vascular resistance (SVR) was calculated. Our primary endpoint (outcome) was the number of hypotension episodes (defined as MAP < 70 mmHg).ResultsUsing univariate analysis, we found no differences between the groups in regards to MAP, HR, CI, or SVR during the perioperative period. The incidence of hypotension was similar in both groups (two patients in each group), as was the incidence of bradycardia (12 patients in CSE, 7 in Epidural;P = 0.2). There were no differences between groups in other hemodynamic measurements including CI and calculated SVR. Analgesia supplementation with fentanyl was more frequently required in the Epidural group (20 vs 6 patients —P = 0.03).ConclusionCombined spinal-epidural anesthesia and epidural anesthesia alone during TKR surgery are associated with the same incidence of hypotension with statistically and clinically similar hemodynamic responses.RésuméObjectifNous avons émis ľhypothèse que ľincidence ďhypotension pendant ľarthroplastie totale du genou (ATG) serait plus faible avec ľanesthésie rachidienne et péridurale combinée (RPC) qu’avec ľanesthésie péridurale seule.MéthodeLors ďune étude prospective, 80 patients ďétat physique ASA I–II, de 40 à 80 ans, subissant une ATG réglée, ont été répartis aléatoirement pour recevoir une anesthésie RPC (groupe RPC, n = 40) ou péridurale seule (groupe péridural,n = 40). Les mesures hémodynamiques comprenaient la tension artérielle moyenne (TAM) oscillométrique, la fréquence cardiaque (FC) et ľindex cardiaque (IC) déterminé par la bio-impédance thoracique; la résistance vasculaire générale (RVG) a été calculée. Notre principal paramètre était le nombre ďépisodes ďhypotension définie par une TAM < 70 mmHg).RésultatsSelon une analyse univariée, il n’y avait aucune différence intergroupe quant à la TAM, la FC, ľIC ou la RVG périopératoires. Ľincidence ďhypotension était similaire dans les deux groupes (deux dans chaque groupe), aussi ľincidence de bradycardie (12 avec ľanesthésie RPC et 7 avec la péridurale; P = 0,2). Les autres mesures hémodynamiques ne présentaient pas de différence intergroupe, y compris ĽIC et la RVG calculée. Un supplément ďanalgésie avec du fentanyl a été plus souvent requis dans le groupe péridural (20 vs 6 patients — P = 0,03).ConclusionĽanesthésie rachidienne et péridurale combinée et ľanesthésie péridurale seule, utilisées pendant ľATG, sont associées à la même incidence ďhypotension et à des réactions hémodynamiques similaires au plan statistique et clinique.

Surgical Myocardial Revascularization versus Percutaneous Coronary Intervention with Drug-Eluting Stents in Octogenarian Patients

OBJECTIVEnOur goal was to compare the clinical outcomes of octogenarian (or older) patients who are referred for either surgical or percutaneous coronary revascularization.nnnMETHODSnWe retrospectively evaluated the outcomes of all patients 80 years of age who had undergone coronary artery bypass grafting (CABG) with an internal mammary artery or had undergone a percutaneous coronary intervention (PCI) with a sirolimus-eluting stent to the left anterior descending artery in our center between May 2002 and December 2006.nnnRESULTSnOf the 301 patients, 120 underwent a PCI, and 181 underwent CABG. Surgical patients had higher rates of left main disease, triple-vessel disease, peripheral vascular disease, emergent procedures, and previous myocardial infarctions (39.7% versus 3.3% [P = .001], 76.1% versus 28.3% [P = .0001], 19.6% versus 7.5% [P = .004], 15.8% versus 2.5% [P = .0001], and 35.9% versus 25% [P = .04], respectively). CABG patients had a higher early mortality rate (9.9% versus 2.5%, P = .01). There were no differences in 1- and 4-year actuarial survival rates, with rates of 90% and 68%, respectively, for the PCI group and 85% and 71% for the CABG group (P = .85). The rates of actuarial freedom from major adverse cardiac events (MACEs) at 1 and 4 years were 83% and 75%, respectively, for the PCI group, and 86% and 78% for the CABG group (P = .33). The respective rates of freedom from reintervention were 87% and 83% for the PCI group, versus 99% and 97% for the CABG group (P < .001). The 4-year rate of freedom from recurring angina was 58% for the PCI group, versus 88% for CABG patients (P < .001). Revascularization strategy was not a predictor of adverse outcome in a multivariable analysis.nnnCONCLUSIONnOctogenarian CABG patients were sicker and experienced a higher rate of early mortality. The 2 strategies had similar rates of late mortality and MACEs, with fewer reinterventions and recurring angina occurring following surgery.

Removal of deadspace volume from arterial catheter: How muchis enough?

Objective To evaluate the amount of volume needed to be removed from arterial catheter systems to compensate for “deadspace” and to allow an accurate measurement of pH and hemoglobin (Hb). Design Twenty patients undergoing heart surgery were evaluated in a steady state after the induction of anesthesia before surgery. Six blood samples were removed from the arterial catheter, the total volume of which was 1.5 mL at 30-sec intervals and measured for pH and Hb. The first sample was then taken after removing 1.5 mL from the tubing. In subsequent samples, the volume removed before sampling increased by 0.5-mL intervals. All other samples were compared with sample number 6, in which 4 mL of volume were removed before measurements. Results The first three samples with volumes of 1.5, 2.0, and 2.5 mL before measurement were inaccurate compared with sample number 6 (p < .000), giving artificially low values for both pH and Hb. There was no significant difference between the values measured in sample numbers 4, 5, and 6 (3.0, 3.5, and 4.0 mL, respectively). Conclusion The amount of volume needed to be removed before measurement from an arterial catheter system, the volume of which is 1.5 mL, is 3 mL to achieve accurate measurements of pH and Hb. Removal of less volume results in an artificially low measurement.

Comparison of radial and bilateral internal thoracic artery grafting in patients with peripheral vascular disease

OBJECTIVESnThe composite T-graft with radial artery (RA) attached end-to-side to the left internal thoracic artery (ITA) provides arterial myocardial revascularization without the increased risk of deep sternal wound infection associated with harvesting 2 ITAs. However, many surgeons are reluctant to use RA in patients with peripheral vascular disease (PVD) due to concerns regarding the quality of the conduit in this subset of patients. The purpose of this study is to compare early- and long-term outcomes of arterial grafting with bilateral ITAs (BITA) to that of single ITA and RA in patients with PVD.nnnMETHODSnBetween 1999 and 2010, 619 consecutive patients with PVD (500 BITAs and 119 single ITA and RA) underwent myocardial revascularization in our institution.nnnRESULTSnOccurrence of following risk factors as female sex, age 70+, diabetes, unstable angina, emergency operation, cerebrovascular disease and chronic obstructive pulmonary disease was higher in the RA-ITA group. The RA-ITA group also had a higher logistic EuroSCORE (22.1 vs 13.3). Operative mortality and occurrence of deep sternal wound infection of the two groups was similar (4.2% vs 5.0% and 2.5% vs 4.0% for the radial and bilateral ITA, respectively). Median follow-up was 9.75 years. Unadjusted Kaplan-Meier 10-year survival of the two groups was similar (44.1% vs 49.6%, P u2009=u20090.7). After propensity score matching (100 pairs), assignment to BITA was not associated with better adjusted survival (hazard ratio 0.593, 95% confidence interval 0.265-1.327, P u2009=u20090.20, Cox model).nnnCONCLUSIONSnIn patients with PVD, complete arterial revascularization with left ITA and RA can be justified with regards to survival.