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D Sisto

Publications and source records attributed to D Sisto.

At least 19 recordsLinked to original sources
PubMed2006

The influence of posterior capsule opacification on scanning laser polarimetry.

PURPOSE: To evaluate the influence of posterior capsule opacification (PCO) on GDx parameters in a population of pseudophakic, non-glaucomatous patients who underwent Nd:YAG laser capsulotomy (YLC). METHODS: The posterior capsules were photographed with a Topcon digital camera and each image was then entered into the EPCO 2000 software and evaluated independently by three examiners. The EPCO 2000 software was used to calculate the fibrosis index (FI) and the pearl index (PI) for the central 1.5, 2.5, and 3.5 mm of the posterior capsule. Scanning laser polarimetry was performed with GDx before and after YLC. We compared the GDx readings obtained before and after the YLC using paired Student's t-test. The parameters that varied significantly after YLC were subsequently used for regression analysis. Stepwise multiple linear regression was used to analyse the impact of the change in the amount of FI and PI on change in GDx parameters after YLC. RESULTS: In total, 158 patients were enrolled (74 men, 84 women). The mean age was 69.46+/-8.83 years (range 46-83 years). The interobserver agreement among the three experts was found to be good (repeatability coefficient R=1.51, 1.49, 1.49 for observer A vs B, A vs C, and B vs C respectively). One-sample Student's t-test show no difference between all GDx parameters before and after YLC except for Symmetry, Superior/Nasal ratio, Inferior Ratio, and Temporal-Superior-Nasal-Inferior-Temporal (TSNIT). Stepwise multiple regression showed that the two variables of greatest significance for changes in Symmetry were the FI in the central 1.5 and the PI in the central 3.5 mm (P=0.02). Superior/nasal ratio was shown to be most strongly correlated to the FI in the central 1.5 mm and PI in the central 3.5 mm (P<0.001), whereas the variable of greatest significance to Inferior Ratio was PI in the central 3.5 mm (P=0.03). Finally, TSNIT was most strongly correlated to FI in the central 1.5 mm and FI in the central 2.5 mm (P<0.001). CONCLUSION: Presence of capsular fibrosis seems to be more clinically relevant in the central zone, whereas pearls tend to be clinically significant in the central 3.5 mm area. Hence, it might be worthwhile assessing the amount of PCO in pseudophakic patients when performing scanning laser polarimetry. Investigators should ensure that the type of PCO and the size of the area analysed are documented in the notes in order to interpret GDx findings appropriately.

Aged↗
PubMed2001

MAST system: a new condensed cardiopulmonary bypass circuit for adult cardiac surgery.

There have been many refinements in cardiopulmonary bypass (CPB) techniques over the past few decades specific to design, materials and function. Despite these improvements, use of the standard length circuit tubing and pump oxygenator alter cellular, biochemical and rheological properties by inducing a systemic inflammatory response, persisting well into the early postoperative phase. We have designed a new condensed CPB circuit, the MAST system, where the oxygenator and the pumps are brought closer to the operating table (within 30 inches) with the help of a series of telescopic swivel steel poles to which they are attached. The control console is retained at the usual remote location of 2ft behind the MAST system. This configuration accomplishes a decrease in tubing length, priming volume and blood circulatory time within the extracorporeal circuit. Early experience of a hundred consecutive cases utilizing the MAST CPB system is presented along with a comparative analysis of prime volume, hemodilution and transfusion parameters of MAST system vs the low prime system, which is another newly developed CPB circuit utilizing a pediatric oxygenator to reduce prime volume and hemodilution.

Adult↗
PubMed2000

Isolated extra-corporeal coronary perfusion circuit for use during off-pump coronary artery bypass grafting.

Cardiovascular surgery would not have developed into its present form without the heart-lung machine. In coronary artery bypass grafting (CABG), cardiopulmonary bypass allows accurate, all site, complete revascularization in a way convenient to the surgeon. The aim of this circuit is to find new ways to reduce invasiveness of CABG and to create new basis conditions for successful coronary bypass grafting on the beating heart. Manipulation of the heart compromises collateral coronary flow, especially to critically narrowed coronaries. This circuit standardizes our method for perfusing blood through the coronary bypass grafts with controlled positive pressure as each distal anastomosis is made, and it preserves collateral coronary flow, while facilitating construction of the remaining distal anastomoses.

Cardiopulmonary Bypass↗
PubMed1995

Arthroscopic lateral portals revisited. A cadaveric study of the safe zones.

Lateral knee portal placement is defined by and divided into five anatomic zones (A through E) beginning just anterolateral to the patellar ligament and proceeding posteriorly at 1-cm intervals. The arthroscopic anatomy and the open dissected lateral knee anatomy are correlated in this study with a fresh frozen cadaver. Zone A includes the anterolateral capsulosynovial layer and zone B includes the anterolateral capsulosynovial layer, anterior portion of the iliotibial tract, and the patellotibial ligament. The lateral capsulosynovial layer and the middle-to-posterior portion of the iliotibial tract comprise zone C. Zone D includes the lateral collateral ligament, the popliteal tendon, and the anterior border of the long head of the biceps femoris tendon. The mid-portion of the long head of the biceps femoris tendon and the peroneal nerve make up zone E. Structures penetrated are defined as safe in zones A, B, and C, and unsafe in zone E. Structures that are potentially penetrable are defined as relatively at risk in zone D. When placing a portal for arthroscopic visualization of the posterolateral compartment of the knee, the placement should be between zone D and the anterior portion of zone E at 90 degrees of knee flexion. This potential space is between the lateral collateral ligament and the anterior portion of the biceps femoris tendon; it enlarges with increasing knee flexion and allows for easier portal placement.

Arthroscopy↗
PubMed1994

Left-to-right ventricular interaction with a noncontracting right ventricle.

UNLABELLED: Left ventricular systole is known to contribute to generation of right ventricular pressure and stroke volume. To study the interactions in a dilated noncontractile right ventricle after cardiopulmonary bypass we created a variable volume, neo-right ventricle by excision and replacement of the right ventricular free wall with a xenograft pericardial patch. We investigated the interactions in eight dogs with neo-right ventricle, instrumented to measure cardiac pressures and cardiac output in control conditions (n = 69) and during partial pulmonary artery occlusion (n = 50). RESULTS: The size of the neo-right ventricle was increased from original right ventricular volume V0 to V1 (V1 = V0 + 54 +/- 23 ml), V2 (V2 = V0 + 124 +/- 85 ml), and V3 (V3 = V0 + 223 +/- 162 ml). Cardiac output increased with increasing left ventricular end-diastolic pressure, indicating that the Frank-Starling mechanism was operating in the left ventricle. However, cardiac output decreased with increasing neo-right ventricular size (p < 0.001) and during pulmonary artery occlusion (p < 0.001). Maximal neo-right ventricular pressure was a linear function of the maximal left ventricular pressure at each neo-right ventricular size and decreased with the increase in neo-right ventricular size (p < 0.001), both in control conditions and during pulmonary artery occlusion (p < 0.004). Stroke work of the neo-right ventricle and left ventricle decreased with increasing neo-right ventricular size (p < 0.002). The relationship between neo-right ventricular stroke work and left ventricular stroke work at different neo-right ventricular sizes was linear both in control conditions and during pulmonary artery occlusion: in control Y = 0.24X (r = 0.968, n = 69); in pulmonary artery occlusion Y = 0.35X (r = 0.986, n = 50). In both conditions the intercept of the linear relationship was not significantly different from zero (p < 0.974 in control; p < 0.614 in pulmonary artery occlusion). The slope was significantly increased in pulmonary artery occlusion (p < 0.001). CONCLUSION: Left ventricular contraction contributes 24% of left ventricular stroke work to the generation of right ventricular stroke work via the septum in the absence of a contracting right ventricle; this increases to 35% in the face of increased pulmonary afterload. This mechanism can maintain adequate global cardiac function in the case of a noncontracting right ventricle while right ventricular volume is kept small and afterload is not increased. The interventricular interaction of the ventricles must be considered when patients with postbypass right ventricular failure are treated.

Animals↗
PubMed1993

Safety and intracardiac function of a silicone-polyurethane elastomer designed for vascular use.

No ideal prosthetic heart valve exists. While polyurethane copolymers possess excellent physical properties, thrombosis and embolism remain a problem and compounds designed to be less thrombogenic have been prone to biodegradation and failure ('cracking'). We tested a new material which has an elastomeric silicone applied to the polymer surface. A hydrophilic film of protamine and gelatin is covalently bonded to the silicone--this obviates the need for preclotting and should permit endothelial growth. The material was tested by implantation during cardiopulmonary bypass as patches in the mitral valve of six weanling sheep (weanling sheep provide a standard model of accelerated calcification for bioprosthetic heart valves). Prosthetic valves constructed from the material were implanted in an additional four animals, but all of these died within 30 days with heavily calcified valves. Four of the six animals with patches survived and were sacrificed 180 days after surgery when the patches were found to be well healed to native tissue, with collagenous ingrowth and partial endothelial covering. Scanning electron microscopy confirmed good healing, tissue ingrowth and good surface endothelium. The material functioned well as a patch in the mitral valve, allowing tissue ingrowth and endothelial growth on the surface of the patch. The material is not able to resist the strains experienced by a mitral valve prosthesis. Prospects for improved polymers for intravascular applications are good.

Animals↗
PubMed1993

Myocardial protection in diffuse coronary artery disease. Intermittent retrograde cold-blood cardioplegia at systemic normothermia versus intermittent antegrade cold-blood cardioplegia at moderate systemic hypothermia.

In order to determine the comparative merits of antegrade cardioplegia at moderate systemic hypothermia versus retrograde cardioplegia at systemic normothermia, we performed coronary artery bypass grafting using intermittent oxygenated blood cardioplegia in 2 sets of 50 consecutive patients with triple-vessel disease (complete occlusion of 1 coronary artery and greater than 90% narrowing of the other 2, with poor distal runoff). Group 1 had antegrade cardioplegia at moderate systemic hypothermia (28 degrees C). Group 2 had retrograde cardioplegia at systemic normothermia. This resulted in no deaths and in no differences in complication rates. Group 2's postoperative need for inotropic agents or vasodilators was significantly less (epinephrine, p < 0.0009; dopamine, p < 0.002; nitroglycerin, p < 0.001). Elevations of CKMB fraction were significantly more common in Group 1: 46% had CKMB levels greater than 9%, versus 16% of Group 2 patients (p < 0.0001). Intraoperative transesophageal echocardiography was performed in 39 Group-1 patients and in 42 Group-2 patients. Development of a new wall-motion abnormality after bypass was significantly only in Group 1 (p < 0.009, by chi 2 analysis). We conclude that retrograde cardioplegia at normothermia provides myocardial protection that equals or surpasses that of antegrade delivery at moderate systemic hypothermia, while avoiding the possible deleterious side effects of hypothermia.

Adult↗
PubMed1992

High-flow femoro-femoral bypass utilizing small cannulae and a centrifugal pump on the venous side.

Femoro-femoral bypass is an established technique in the armamentarium of cardiac surgeons, but poor venous drainage usually restricts the flow rate that can be achieved. We describe a technique whereby full flow ( greater than 2.41 l/min/m 2 femoro-femoral bypass) can be achieved with a 17 F arterial and a single 21 F venous cannula placed percutaneously or via a cut-down. Transoesophageal echo is used to position the tip of the venous cannula accurately in the right atrium. The circuit includes a centrifugal pump on the venous side, pumping into a reservoir; a conventional roller pump delivers blood through the arterial cannula. A parallel arrangement allows the centrifugal pump to be excluded from the circuit at any stage. The system allows flow rates over 2.4 l/min/m 2 despite the size of the venous cannula; without the centrifugal pump working maximal flow rates are under 1.5 l/min/m 2. The right side of the heart is totally decompressed and there is no need to add volume or vasopressors to maintain the desired full flow rate. Once the chest is open, perfusion may continue as before or gravity drainage can be utilized after stopping the centrifugal pump; venous return may be augmented by placing additional cannulae. If desired, slowing drainage by the centrifugal pump temporarily permits the blind placement of a coronary sinus cannula without entraining air.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

Massive intraoperative pulmonary embolism.

Intraoperative massive pulmonary embolism is extremely rare. We describe such a case in a patient treated for a prolonged period preoperatively with intravenous heparin after an acute myocardial infarction and unsuccessful attempt at angioplasty, emphasizing that the problem should be borne in mind to facilitate expeditious and appropriate management. A clue to the diagnosis is interruption of venous return that is not due to a kink in the cannulae.

Aged↗
PubMed1991

New applications of two-dimensional transesophageal echocardiography in cardiac surgery.

This article describes new applications of two-dimensional transesophageal echocardiography (2D-TEE), including (1) detection of pleural fluid (PF) and atelectasis (AT), and (2) evaluation of various cannulation techniques. The left and right pleural spaces were visualized by rotating the probe counterclockwise and clockwise, respectively, from the four-chamber view. PF was depicted as a crescent-shaped echo-free space, enclosed by the lung and posterior chest wall on both sides. AT was often accompanied by PF and was depicted as a less echogenic area in the lung parenchyma. During removal of PF, the echo-free space gradually decreased in size to the point of disappearing completely, while the lung parenchyma expanded and became more echogenic. TEE was advantageous in detecting PF and AT located in the most dorsal parts of the pleural space and lung parenchyma. The aorta acted as an acoustic window on the left side. TEE was found useful in evaluating the cannulae position of the intraaortic balloon pump (IABP) and ventricular assist device (VAD), and femoral cannulae for cardiopulmonary bypass (CPB). During use of the IABP, the chamber and shaft were visualized clearly and both malposition of the catheter tip and malfunction of the balloon were easily detected. For VAD, TEE readily showed the collapse of the ventricular cavity due to excessive drainage of blood from the left ventricle, as well as the favorable result of immediate reduction of flow rate. For femorofemoral extracorporeal bypass, TEE detected improper position of the venous cannula. These new applications of TEE can be performed with minimal manipulation of the probe, enabling early detection of the problems and initiating timely and appropriate therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1991

Surgical correction of posttraumatic VSD via the right atrium.

We report the cases of four patients seen with ventricular septal defects (VSDs) resulting from penetrating chest trauma; initial surgical management was via left thoracotomy and comprised relief of tamponade and suture of the surface cardiac wound. A VSD was suspected in all four patients postoperatively on the basis of a holosystolic murmur as confirmed with two-dimensional echo and angiography. Elective surgical repair was undertaken on cardiopulmonary bypass with bicaval cannulation and cardioplegic arrest. The interventricular septum was approached through the right atrium (no attempt was made to free the anterior surface of the right ventricle from adhesions). Three defects were closed directly and one was closed with a pericardial patch. The surgical correction of posttraumatic VSD from a penetrating injury can be safely and effectively achieved via a right atrial approach.

Echocardiography↗
PubMed1989

Cardiac surgery in human immunodeficiency virus (HIV) carriers.

UNLABELLED: Intravenous drug addicts have always been at risk for acquiring infective endocarditis. In the United States in recent years, as many as 50% of addicts have become infected also with the human immunodeficiency virus (HIV). Since testing became available in late 1984, we have knowingly performed open cardiac surgery for endocarditis 11 times in HIV-positive patients. In 7, signs of infection were still presented at the time of surgery. Four died within 2 months of continued or recurrent sepsis. The others are alive, although 1 has returned to IV drug abuse. Open heart surgery was performed 4 times in patients whose endocarditis had been cured by antibiotics but who were left with destroyed valves and severe congestive cardiac failure. All these patients left hospital alive and well. One has since died of AIDS. Ten addicts with endocarditis coming to surgery in the pre-AIDS era had similar valvular pathology but only 2 with uncontrolled infection. All were cured by the combination of antibiotics and surgery. CONCLUSIONS: in HIV-positive patients with endocarditis, continued sepsis despite appropriate antibiotic therapy signals a potentially very serious prognosis which may be due to an already seriously impaired immune state. By contrast, in the absence of uncontrolled infection, HIV-positive patients appear to have a normal response to open cardiac surgery. Data on the risk to the patient of progressing to AIDS and the risk to the surgical team of acquiring HIV infection are unknown. Testing is vital for answering these questions.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Replacement of mitral valve chordae with autologous pericardium in dogs.

Glutaraldehyde-tanned autogenous pericardium was compared with untreated autogenous pericardium as a tissue for replacement of anterior chordae tendinae of the mitral valve. Tanned autogenous pericardial chordae have a marked fibrous reaction at their healing ends but retain central pliability. Untreated autogenous pericardial chordae become uniformly fibrosed and stiff. Both retain their length, heal well to the papillary muscle and cusp, and are considered as potentially useful chordal substitutes in the right circumstances. Some of the response of the host to implanted tanned xenograft tissue must be related to the consequences of tanning rather than a reaction to foreign tissue.

Animals↗