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Biomedical subjects

Roberto Lorusso

Publications and source records attributed to Roberto Lorusso.

17 recordsLinked to original sources

Mitral valve periprosthetic leakage: Anatomical observations in 135 patients from a multicentre study.

OBJECTIVE: Prosthetic valve dysfunction after mitral valve replacement (MVR) may be caused by several factors, which often lead to repeated surgery. One of the most frequent determinants of reoperation is periprosthetic leakage (PPL). A few published reports have analysed PPL incidence and postoperative results after MVR, but no specific attention has been paid towards the potential relation between anatomical factors and PPL occurrence, particularly not bacterial-related. The aim of this study was to evaluate the location of PPL after MVR through a multicentre retrospective study. METHODS: Between January 1985 and November 2005, 135 patients underwent reoperation at four institutions because of PPL after MVR and met the study inclusion criteria. The mitral valve annulus (MVA) was analysed in a clockwise format, indicating 12 o'clock as the mid-point of anterior annulus as viewed from the atrium. RESULTS: Overall hospital mortality was 3.7% (five patients). Repair of PPL was carried out in 83 cases whereas prosthetic valve replacement was necessary in 52 cases. The total number of sectors involved in PPL was 244. PPL occurred more frequently between hour 5 and hour 6, and hour 10 and hour 11, with the risk of leakage being, 2.8 and 2.0 times higher, respectively, than in any other portion of the MVA. CONCLUSIONS: Our study suggests that PPL occurs more frequently at antero-lateral and postero-medial segments of MVA. This finding might be linked to unusual anatomical and functional factors of the MVA and may call for adjunctive care to these sectors of MVA when performing suture placement during MVR.

Aged↗

Functional effects of nitric oxide-releasing aspirin on vein conduits of diabetic patients undergoing CABG.

BACKGROUND: Type 2 diabetes mellitus (DM) is known to negatively affect biological properties of venous vasculature, and, particularly, to reduce endothelium-derived nitric oxide release. This condition might influence venous graft function following coronary artery bypass surgery (CABG). The aim of this study was to evaluate the functional effects of a NO-releasing aspirin (NORA) on vein grafts (VG) of diabetics and control patients undergoing elective CABG. METHODS: In 40 consecutive ischemic heart disease patients, the effects of NORA were tested on segments of saphenous vein conduits harvested during elective CABG. Twenty patients had type-2 DM (mean age 69+/-2), whereas 20 patients had no DM (NDM) and represented the control group (mean age 67+/-4). Functional responses were tested by exposing VGs to NORA and to standard vasoactive agents in an organ-bath preparation. Histological features of VGs were also assessed by light and electronic microscopy. RESULTS: Significant impairment of endothelial-dependent vasodilation (acetylcholine induced) was documented in VGs of DM subjects. NORA induced a significant and comparable vascular relaxation in all venous segments of NDM and DM patients (56+/-12% of maximal relaxation vs 61+/-11% in the control group, respectively). Histology showed variable extent of vascular layer and cellular abnormalities in VGs of diabetics (intimal hyperplasia, calcific deposition, endothelial cell degeneration) likely responsible of the endothelial functional impairment, whereas control group VG showed preserved structures. CONCLUSIONS: This preliminary study confirms the impairment of endothelium-dependent vasodilative property of VGs in DM patients. It also indicates that NORA effectively induces vasodilation of VGs which was effective also in DM patients thereby representing a promising therapy for diabetics undergoing CABG with the use of VGs, although further studies are mandatory to conclusively assess the safety and benefits of this pharmacological agent.

Acetylcholine↗

Epidemiology and cardiovascular risk factors of aortic stenosis.

The abnormalities of aortic valve morphology and function represent the most common cardiac-valve lesion particularly in elderly. The etiology of aortic stenosis is degenerative-calcific in the majority of patients. Many risk factors seems to be linked to the calcification and the stenosis of the aortic valve but they must be confirmed. In this review the etiology and the possible physiopathology of the aortic valve stenosis is discussed.

Aortic Valve Stenosis↗

Similar long-term results of mitral valve repair for anterior compared with posterior leaflet prolapse.

OBJECTIVE: The results of mitral valve repair for anterior leaflet prolapse have been less gratifying than those reported for posterior leaflet prolapse. We compared the long-term durability of 2 different surgical techniques: the edge-to-edge repair, which is used for the treatment of anterior leaflet prolapse, and quadrangular resection, which has been adopted for correction of posterior leaflet prolapse. METHODS: From 1991 through April 2004, 133 patients with anterior leaflet prolapse and 605 with posterior leaflet prolapse caused by degenerative mitral disease underwent valve repair. The edge-to-edge repair was used for correction of anterior leaflet prolapse, and quadrangular resection of the posterior leaflet, with or without sliding plasty, was used for correction of posterior leaflet prolapse. All patients received a concomitant annuloplasty procedure. RESULTS: No hospital deaths occurred in the anterior leaflet prolapse group, whereas 2 (0.3%) patients died in the posterior leaflet prolapse group (P = .7). Follow-up was 100% and 97.2% complete in the anterior and posterior leaflet prolapse groups, respectively. At 10 years, overall survival was 91% +/- 4.06% for anterior leaflet prolapse and 93.5% +/- 1.81% for posterior leaflet prolapse (P = .18), and freedom from cardiac death was 95.8% +/- 2.83% for anterior leaflet prolapse and 97.4% +/- 0.95% posterior leaflet prolapse (P = .27). Freedom from reoperation was 96% +/- 2.3% in the anterior leaflet prolapse group and 96.5% +/- 1.18% in the posterior leaflet prolapse group (P = .37). At follow-up (mean, 4.5 +/- 3.12 years; range, 1 month-13.2 years), New York Heart Association functional class I or II was documented in 93.2% of patients in the anterior leaflet prolapse group and 92.8% in the posterior leaflet prolapse group (P = .98). CONCLUSIONS: The long-term results of the edge-to-edge repair in the setting of anterior leaflet prolapse are similar to those obtained with quadrangular resection for the treatment of posterior leaflet prolapse.

Echocardiography, Transesophageal↗

Aortic valve periprosthetic leakage: anatomic observations and surgical results.

BACKGROUND: One of the most frequent causes of reoperation after heart valve replacement is periprosthetic leakage (PPL). Previous studies have failed to determine whether PPL is linked to specific anatomic details. The aim of this study was to examine the location within the aortic annulus where PPL occurs, and to evaluate the postoperative outcome after surgical correction. METHODS: Between January 1985 and December 2001, 28 patients underwent reoperation because of PPL after aortic valve replacement. The aortic annulus was analyzed in a clockwise format with hour 1 corresponding to the commissure between the left coronary sinus and the right coronary sinus, hour 5 to the commissure between the right coronary sinus and the noncoronary sinus, and hour 9 to the commissure between the noncoronary sinus and the left coronary sinus. RESULTS: Overall operative mortality was 7.1% (2 patients). Repair of PPL was carried out in 8 patients whereas prosthetic valve replacement was necessary in 20 patients. Urgency or emergency operation (p < 0.0037), preoperative New York Heart Association class IV (p < 0.04), need for prosthetic valve replacement (p = 0.05), and implant of mechanical valve (p = 0.031) were independent determinants of dismal prognosis. Periprosthetic leakage occurred more frequently between hour 4 and hour 8 (19 patients), with the risk of leakage being two times greater than in other annular areas. CONCLUSIONS: Our study suggests that PPL occurs more frequently in a specific portion of the peculiar aortic annulus. In case of PPL diagnosis, a timely reoperation might decrease operative risks by avoiding emergency procedures and unfavorable preoperative clinical conditions, and preventing prosthetic valve replacement.

Aortic Valve Insufficiency↗

Use of novel nonfluoroscopic three-dimensional electroanatomic mapping system to monitor and analyze heart surgery in animal models.

BACKGROUND: The new method of three-dimensional (3D) electroanatomic mapping was presented as an important tool for cardiac imaging and intervention. We present herein the first use of this technology for the monitoring, analysis, and development of cardiac surgery at the preclinical stage. METHODS: The method is based on utilizing a locatable catheter connected to an endocardial mapping and navigating system, to accurately establish the location and orientation of the tip of the mapping catheter and simultaneously record its local electrogram. The 3D geometry of the beating cardiac chamber is reconstructed in real time. The system was tested on six goats that underwent dynamic cardiomyoplasty. Two maps of each animal were performed: preoperative and postoperative during the stimulation protocol of the skeletal muscle. RESULTS: The electroanatomic mapping system provided detailed maps of the left ventricle during the stimulation protocol, which demonstrated a striking geometric difference between the assisted and the unassisted beats. These geometric changes are best described by referring to left ventricular long-axis movements (22.3 +/- 3.8 degrees vs 3.4 +/- 1.6 degrees, p < 0.001), center-of-mass movements (10.4 +/- 3.0 mm vs 3.9 +/- 1.6 mm, p < 0.005), and the changes in upward movement viewed along the base (7.9 +/- 1.9 mm vs 3.6 +/- 1.7 mm, p < 0.01), middle (13.8 +/- 4.0 mm vs 7.3 +/- 1.8 mm, p < 0.005), and the apex of the heart (28.1 +/- 4.5 vs 5.3 +/- 2.3 mm, p < 0.001) [mean +/- SD]. CONCLUSIONS: The 3D electroanatomic mapping system allows detailed reconstruction of the left ventricular geometry and a clear view of the difference between the assisted and the unassisted beats. This novel monitoring system may serve as an important tool for the analysis and development of new techniques in cardiac surgery.

Animals↗

The triple-orifice repair: a new technique for the treatment of mitral regurgitation in severe Barlow's disease.

We report a case of severe Barlow's disease with a very complex pathology, in which we applied the "edge-to-edge" technique, creating a triple-orifice mitral valve. Different techniques should be used to correct a similar valve defect; the combination of different surgical procedures and the valve pathology may influence the post-repair recurrence of regurgitation. We believe that it is better to perform a simple and reproducible repair than to carry on with combined complex procedures that could increase the risk of a suboptimal outcome.

Adult↗

Influence of type 2 diabetes on functional and structural properties of coronary artery bypass conduits.

Recent studies have reported a high incidence of postoperative unfavorable cardiac-related events in patients with diabetes who underwent coronary artery bypass grafting (CABG). Structural and functional characteristics of CABG conduits, which have been shown to play an important role in patient outcome after myocardial revascularization, have not been fully investigated in diabetic subjects. Therefore, we sought to determine the influence of adult-onset diabetes on vasoreactivity and morphological profile of venous and arterial grafts. Of the 160 consecutive patients enrolled in the study, 90 were diagnosed with type 2 diabetes and 70 did not have diabetes (control group). All patients underwent evaluation of glucose control before surgery. Tissue specimens were collected from left internal thoracic artery (LITA) and saphenous vein (SV) grafts harvested during elective CABG. Functional tests were performed to assess contractile and vasodilative responses of bypass conduits. Histological evaluation was carried out to examine vessel wall structure. Univariate and multivariate analyses were performed to correlate the preoperative factors related to the control of the endocrine disorder with histological findings. Patient medical history and demographics did not differ between the groups. Diabetic patients showed significant microalbuminuria and higher plasma levels of C-peptide and GHb as compared with nondiabetic subjects. Functional tests of the LITA segments revealed no difference between groups with regard to contractile and vasodilative responses. In contrast, significant impairment in the endothelium-related vasodilation of the SV grafts was observed in diabetic subjects. Histological studies showed structural preservation of the arterial conduits in both groups. However, marked intimal abnormalities (also atherosclerotic calcified plaques) were detected in SV grafts harvested from diabetic patients. Logistic regression analysis showed that high levels of proteinuria and GHb were independent predictors of advanced structural degeneration of SV conduits. Treatment modality, duration of diabetes, and other demographic or metabolic factors were found to have no influence on the morphological characteristics of SV conduits. In conclusion, biological properties of LITA conduits for CABG were preserved in diabetic patients. However, these patients frequently showed impairment of the endothelium-dependent vasorelaxation and intimal degeneration of SV grafts. The extent of structural abnormalities of SV grafts was inversely correlated with the efficacy of the metabolic control of the endocrine disorder. Further studies are required to conclusively correlate preoperative SV graft abnormalities with postoperative conduit patency rate and the occurrence of adverse cardiac-related events in diabetic subjects.

Administration, Oral↗

Effects of acute dynamic cardiomyoplasty in a goat model of chronic ventricular dilatation: part 1.

BACKGROUND: The acute effects of cardiomyoplasty in an experimental model of chronic dilated heart have not been thoroughly investigated. Therefore, a model of chronic left ventricular (LV) dilatation was created to accurately determine actual changes shortly after passive and active wrapped skeletal muscle. METHODS: A carotid-jugular shunt model in 8 goats was used to induce progressive dilatation of the cardiac ventricles. Geometric modifications induced by the arteriovenous shunt were monitored by transthoracic echocardiography. After 8 weeks, cardiomyoplasty was performed, and the acute hemodynamic changes obtained with static cardiomyoplasty soon after the wrapping procedure were determined. Hence, hemodynamic variables recorded during assisted cardiac beats were then compared with data collected with unassisted cardiac beats using the conductance catheter method to generate pressure-volume loops. RESULTS: During electrical stimulation of the unconditioned skeletal muscle wrapped around the dilated left ventricle, a significant increase in stroke volume (117 +/- 48 mL versus 87 +/- 38 mL; p < 0.05) was observed. Early wrapped latissimus dorsi muscle activation also induced a reduction in LV end-systolic volume (from 51 +/- 28 mL to 27 +/- 14 mL; p < 0.05) when compared with unassisted LV contraction. CONCLUSIONS: In a chronic model of cardiac dilatation, acute dynamic cardiomyoplasty was shown to increase LV contractile performance and reduce LV volume. Further evaluation is necessary to show the effects of a conditioned wrapped muscle on LV systolic function and dimensions in the long-term.

Animals↗

Effects of chronic cardiomyoplasty on ventricular remodeling in a goat model of chronic cardiac dilatation: part 2.

BACKGROUND: Reduction of ventricular dilatation, rather than direct improvement of pump function, has been suggested to be the main working mechanism of dynamic cardiomyoplasty (CMP). This working mechanism was examined in the goat using a chronic cardiac dilatation model induced by the creation of a cervical arteriovenous shunt and submitted to passive and active CMP. METHODS: Fourteen female goats underwent surgical creation of a shunt between the left carotid artery and the jugular vein. Seven goats had no additional operation (control group). The other 7 goats (CMP group) underwent CMP approximately 8 weeks after the creation of the shunt. The wrapped left latissimus dorsi muscle was left unstimulated for 2 weeks, and subsequently stimulated electrically for a 3-month period, using a 1:4 muscle-to-heart contraction ratio. Hemodynamic measurements included heart catheterization and determination of left ventricular (LV) pressure-volume relations by means of the conductance catheter method at baseline, after 8 weeks (only in the CMP group), and after 5 months. Transthoracic echocardiography was performed just before opening the AV shunt and every 2 weeks thereafter. RESULTS: Significant ventricular enlargement, as well as persistent increase in filling pressures, were observed after 8 weeks. Animals in the control group dilated further beyond 2 months (LV end-diastolic diameter from 39 +/- 2 to 67 +/- 6 mm). In contrast, the ongoing LV dilatation process was stopped by passive CMP, and LV end-diastolic diameter significantly decreased after electrical activation of the wrapped skeletal muscle (from 63 +/- 7 to 42 +/- 6 mm). Cardiomyoplasty also significantly increased the slope of the end-systolic pressure-volume relation (elastance) when compared with pre-CMP values (from 0.9 +/- 0.2 to 1.7 +/- 0.5 mm Hg/mL), which indicated an improvement of the LV contractile state. No significant hemodynamic effects could be observed at the tuned stimulation settings on a beat-to-beat basis during electrical muscle stimulation. CONCLUSIONS: The contribution of CMP to LV dimension and contractility appeared to be either passive or active, and this study suggests the importance of stimulating the latissimus dorsi muscle to enhance the girdling effects of the wrapped latissimus dorsi muscle and to improve LV contractility.

Animals↗

Hemodynamic analysis of descending versus ascending aortomyoplasty, and comparison with intra-aortic balloon pump.

OBJECTIVE: Descending and ascending aortomyoplasty are two surgical procedures intended to induce hemodynamic benefits similar to those of the intra-aortic-balloon-pump (IABP). To date, there have been no studies comparing the two surgical techniques. The objective of this study was to compare coronary blood flow augmentation and afterload reduction as produced by descending and ascending aortomyoplasty counterpulsation METHODS: Twenty-two mongrel dogs (18-35 kg) underwent IABP application (n=7), descending (n=8), or ascending (n=7) aortomyoplasty. Left anterior descending (LAD) coronary artery blood flow was measured using a Transonic Doppler flow probe. Left ventricular pressure as well as aortic pressures proximal and distal to either the aortomyoplasty site or the IABP position were monitored continuously. RESULTS: Descending aortomyoplasty induced higher elevation in the LAD blood flow during assisted beats (27% from 10.8+/-4 to 13.8+/-6 ml/min, P<0.001) than that induced by either ascending aortomyoplasty (19% from 11.7+/-5 to 14+/-5 ml/min, P<0.001) or IABP counterpulsation (18% from 8.6+/-3 to 10.2+/-4 ml/min, P<0.001). Conversely, while ascending aortomyoplasty reduced the left ventricular end-diastolic pressure by 16% (from 60+/-18 to 50+/-22 mmHg, P<0.001), similar to the 16% after load reduction achieved by the IABP counterpulsation, descending aortomyoplasty failed to induce afterload reduction. CONCLUSIONS: Descending aortomyoplasty produces higher coronary blood flow augmentation than either ascending aortomyoplasty or IABP. However, afterload reduction comparable to that achieved by IABP was observed only with ascending aortomyoplasty and not with descending aortomyoplasty.

Animals↗

Perioperative hemodynamic and geometric changes of the left ventricle during cardiomyoplasty in goats with dilated left ventricle.

OBJECTIVE: Clinical data have suggested the occurrence of temporary short-term deterioration of the heart following cardiomyoplasty. The purpose of this study was to monitor the short-term hemodynamic effects of cardiomyoplasty in a goat model of a dilated left ventricle, using conductance catheters (ie, pressure-volume loops) and cardiac output measurements. METHODS: Eight female goats underwent acute cardiomyoplasty 8 to 12 weeks after left ventricular (LV) dilatation was induced by a carotid jugular arteriovenous shunt. The cardiomyoplasty procedure was monitored using a Swan-Ganz catheter for cardiac output measurements and a 12-electrode (dual-field) conductance catheter to LV pressure-volume loops. RESULTS: After wrapping the heart with the latissimus dorsi muscle, there was a significant reduction in both cardiac output and LV end-diastolic volume (LVEDV) at 10 min. Partial recovery was observed 45 min later. CONCLUSION: A decrease in both cardiac output and LVEDV was observed following myocardial wrapping. This may explain some of the perioperative and postoperative morbidity and mortality observed following cardiomyoplasty.

Animals↗

Does growth hormone play a role in chronic heart failure?

Experimental and clinical studies have recently demonstrated that the growth hormone-insulin-like growth factor-I (GH-IGF-I) system is involved in the regulation of cardiac structure and function. Patients with acromegaly have an increased propensity of developing cardiovascular complications, such as ventricular hypertrophy with interstitial fibrosis. Conversely, patients with GH deficiency can exhibit ventricular dysfunction, increased vascular thickness, and an increased number of atheromatous plaques. In both groups of patients these abnormalities may be partially reverted by normalizing GH-IGF-I levels. In experimental or human chronic heart failure (CHF), GH administration increases ventricular mass and cardiac performance and reduces pulmonary vascular resistance. The mechanism by which this occurs is still unclear, but seems to involve calcium channels and non-endothelium-mediated vasodilatation. Randomized trials studying CHF patients contradict these results, highlighting that, in patients with heart failure, the response to GH therapy appears to be variable, and is probably influenced either by acquired GH resistance or by baseline levels of hormones. Due to the small number of patients examined to date, larger, randomized, controlled studies are needed.

Animals↗