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Biomedical subjects

Q Caretta

Publications and source records attributed to Q Caretta.

At least 19 recordsLinked to original sources
PubMed2000

Detection of false lumen perfusion at the beginning of cardiopulmonary bypass in patients undergoing repair of aortic dissection.

OBJECTIVE: In patients undergoing surgical repair of aortic dissection, false lumen perfusion during cardiopulmonary bypass may produce central nervous system damage, myocardial ischemia, aortic rupture, and death. We describe a method to detect false lumen perfusion at the beginning of retrograde aortic perfusion that may prevent these complications. DESIGN: Sonicated albumin microbubbles (8 mL) were injected through a side branch of the extracorporeal circulation line to detect true lumen and/or false lumen perfusion of the thoracic aorta at the beginning of cardiopulmonary bypass. Transesophageal echocardiography was used to image aortic perfusion. SETTING: The study was performed in a cardiac surgery theater. PATIENTS: A total of 27 consecutive patients undergoing operation for Type I aortic dissection were studied. INTERVENTIONS: All patients underwent surgical repair of aortic dissection and retrograde aortic perfusion through one femoral artery. MEASUREMENTS AND MAIN RESULTS: Patients were divided into three groups: Group I, those having adequate true lumen perfusion: brisk appearance and washout of contrast in the true lumen with no, poor, or delayed opacification of the false lumen; Group II, those having mixed true lumen and false lumen perfusion: simultaneous opacification of both lumens; Group III, those having inappropriate false lumen perfusion: same criteria as for adequate true lumen perfusion applied to the false lumen. The true lumen was perfused in 13 patients, both lumens in 11 patients, and false lumen alone in three patients. In these three patients, cannulation was repeated through the contralateral femoral artery with restoration of true lumen perfusion; the first patient died of diffuse cerebral ischemic damage and renal failure, another one experienced temporary postoperative monoparesis, and the last had no neurologic sequelae. CONCLUSIONS: Contrast echocardiography allows immediate detection of retrograde aortic perfusion during cardiopulmonary bypass and may help prevent neurologic complications and death in patients with Type I dissection.

Adult↗
PubMed1999

Coronary Doppler intensity changes during handgrip: a new method to detect coronary vasomotor tone in coronary artery disease.

OBJECTIVES: This study evaluates whether a quantitative measurement of Doppler intensity during handgrip may disclose coronary vasomotor dysfunction in patients with coronary artery disease (CAD). BACKGROUND: Atherosclerotic coronary segments show an exaggerated constrictive response to handgrip. The intensity of the scattered Doppler signal is proportional to the number of blood cells flowing through the vessel, and should be reduced during vasoconstriction. Therefore, changes in coronary flow during handgrip may be detected by measuring Doppler intensity rather than velocities. METHODS: The distal left anterior descending coronary artery (LAD) was imaged by high-resolution transthoracic color Doppler echocardiography during handgrip in 47 patients: 15 with normal coronary arteries and 32 with significant CAD involving the LAD. The Doppler signal was acquired at 70 dB dynamic range at baseline, 30-s handgrip and 5 min recovery. Peak and mean flow velocity, pressure half-time, deceleration time (ms), deceleration rate (cm/s2) and mean gray level intensity (intensity units [IU]) of the Doppler spectrum were measured in diastole. RESULTS The velocity parameters did not change significantly during handgrip both in normal and CAD patients. The Doppler intensity significantly decreased during handgrip (from 87.0 +/- 32.8 to 57.7 +/- 35.3 IU; p < 0.001) in patients with CAD, and it increased or remained unchanged in normals (from 74.1 +/- 27.3 to 85.1 +/- 31.2 IU; p = NS). The sensitivity of Doppler intensity in detecting CAD was 84.4%, specificity 93.3%, negative predictive value 73.7% and positive predictive value 96.4%. CONCLUSIONS: Doppler intensity measured by transthoracic echocardiography during handgrip allows the detection of CAD and coronary vasomotor dysfunction.

Blood Flow Velocity↗
PubMed1997

Collateral flow prevents unintentional myocardial ischemia during antegrade cardioplegia in patients undergoing coronary artery bypass grafting.

OBJECTIVE: We evaluated, in the prevention of perioperative unintentional myocardial ischemia, the role of coronary collateral flow in patients with left anterior descending coronary artery stenosis or occlusion who underwent elective coronary artery bypass grafting. METHODS: Coronary lesions and collaterals were assessed by coronary angiography in 21 patients. Anteroseptal myocardial viability was evaluated by dobutamine echocardiography. Antegrade perfusion of cardioplegic solution was assessed by myocardial contrast echocardiography. Time-intensity curves were generated from the anteroseptal region. Twelve parameters were measured and averaged in the following four groups of patients: those with stenosis of the left anterior descending artery and poor collaterals; those with stenosis of the left anterior descending artery and good collaterals; those with occlusion of the left anterior descending artery and good collaterals; and those with occlusion of the left anterior descending artery and poor collaterals. RESULTS: Time-intensity curves were significantly different in patients with stenosis versus occlusion of the left anterior descending artery (p < 0.005); multiple comparisons with Bonferroni's correction showed that this difference was mainly a result of the impact of collateral circulation (p < 0.01). However, the role of collaterals was nonsignificant within the groups with stenosis and occlusion of the left anterior descending artery. Patients with occlusion of the left anterior descending artery and good collaterals had perfusion parameters similar to those of patients with stenosis of the left anterior descending artery (p = not significant), except for the ascending slope and time to peak values (p < 0.05 and p < 0.01, respectively), which reflected a higher flow resistance in the collateral circulation. Regional systolic function after coronary artery bypass grafting was depressed in patients with poor collaterals and poor perfusion of cardioplegic solution, as compared with findings in other subgroups. CONCLUSIONS: Incomplete myocardial protection may impair the early recovery of function after coronary artery bypass grafting.

Cell Survival↗
PubMed1996

Primary repair of coarctation of the thoracic aorta by patch graft aortoplasty. A three-decade experience and follow-up in 60 patients.

OBJECTIVES: The present report is a critical review on primary repair of aortic coarctation by patch aortoplasty on the basis of over 30 years surgical experience. METHODS: Since 1962, 60 patients (mean age 9.4 +/- 4.8 years, range 2-25 years), affected by aortic coarctation, underwent patch aortoplasty repair. During the operation protective guidelines were adopted: additional external Dacron was placed around the repaired site in cases of friable host tissue, the aortic ridge was not excised to leave the posterior aortic wall intact, and the patent ductus arteriosus or ligamentum arteriosum was transected and sutured. Prophylactic measures of neurologic sequelae were: dual pressure monitoring, sequential aortic clamping, surgical shunt or left heart bypass associated with moderate hypothermia when the distal aortic pressure was less than 50 mmHg. RESULTS: No early deaths occurred. The overall survival rate was 92.77 +/- 4.04% at 31 years from surgery. Three late deaths occurred. Pressure gradients across the patch ranged between 9 and 20 mmHg. Late aneurysm occurred in one patient (1.3%), 2 years after bacterial endocarditis had developed on a biscuspid aortic valve. CONCLUSIONS: Patch aortoplasty is an effective and safe surgical procedure for primary repair of isthmic aortic coarctation when other surgical techniques cannot be performed.

Adolescent↗
PubMed1995

Papillary muscle perfusion pattern. A hypothesis for ischemic papillary muscle dysfunction.

BACKGROUND: The pathogenesis of posterior papillary muscle dysfunction is poorly understood. We hypothesized that papillary muscle perfusion pattern may explain the higher prevalence of posterior papillary muscle dysfunction after myocardial infarction. METHODS AND RESULTS: Twenty patients were monitored by transesophageal echocardiography during coronary surgery. Superselective coronary graft injections of 0.2 to 0.5 mL of sonicated albumin microbubbles were performed to assess graft patency and papillary muscle perfusion. Thirty-five graft injections were analyzed: 13 in the right coronary artery, 15 in an obtuse marginal branch, 1 in the left anterior descending coronary artery, and 6 in the first diagonal branch. The posterior papillary muscle was opacified in 16 patients, 11 from the right coronary artery and 5 from one obtuse marginal branch. In 10 of 16 patients (63%), the papillary muscle was perfused by one vessel, while in 6 of 16 (37%), it was perfused by two vessels. The anterior papillary muscle was opacified in 14 patients. Ten patients (71%) had double-vessel and 4 (29%) had single-vessel supply. In the subgroup of 10 patients with old inferior myocardial infarction, mitral regurgitation was present only among those 6 with single rather than double blood supply (P < .05). CONCLUSIONS: Myocardial infarction may cause papillary muscle dysfunction when the blood supply is provided by one rather than two vessels, as is more frequently the case with the posterior rather than the anterior papillary muscle.

Adult↗
PubMed1995

Low-dose dobutamine echocardiography predicts the early response of dysfunctioning myocardial segments to coronary artery bypass grafting.

Dobutamine echocardiography has recently been introduced for use in identification of viable myocardium in patients with acute myocardial infarction and prediction of the response of dysfunctioning myocardial segments to coronary angioplasty. The aim of this study was to evaluate whether this test may be used to predict the early response of dysfunctioning myocardial segments to surgical revascularization. We studied 30 patients with three-vessel disease and chronic, stable angina pectoris during coronary artery bypass grafting (CABG). Patients were monitored by intraoperative transesophageal echocardiography in the transgastric short-axis view at the papillary muscle level. The left ventricle was divided into eight segments; and 240 myocardial segments were analyzed. Percentage of systolic wall thickening (PSWT) was calculated in each segment at baseline (early after pericardiectomy), before bypass during dobutamine infusion (5 micrograms/kg/min), and after separation from cardiopulmonary bypass. Segments showing PSWT < 30% at baseline were considered dysfunctional. Segments showing an increase in PSWT > 10% during dobutamine infusion were considered responders. Segments showing an increase in PSWT < 10% during dobutamine infusion were considered nonresponders. At baseline, 161 (67%) of 240 segments had PSWT < 30% (dysfunctioning segments). During dobutamine, 98 (60%) of these segments increased PSWT > 10% (from 11.3% +/- 7.6% to 24.2% +/- 12.0%, p < 0.01; responder segments), and 63 (40%) increased PSWT < 10% (from 10.2% +/- 4.9% to 8.3% +/- 5.5%, p value not significant [NS]; nonresponder segments).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Intraoperative contrast echocardiography for assessment of the surgical repair of coronary artery fistula.

We report two cases of acquired coronary fistula in whom fistula flow and surgical repair were evaluated intraoperatively by contrast echocardiography. Surgical repair was carried out through the left atrium because of the associated surgical procedure on the mitral valve. Contrast echocardiography allowed easy identification of the fistula openings in the left atrium and intraoperative control of the efficacy of the surgical closure. Contrast echocardiography is an ideal tool for the intraoperative diagnosis of effective interruption of a coronary fistula.

Arterio-Arterial Fistula↗
PubMed1993

Mechanisms of incomplete cardioplegia distribution during coronary artery surgery. An intraoperative transesophageal contrast echocardiography study.

BACKGROUND: Cardioplegia is used to protect the myocardium from ischemic injury during open-heart surgery. However, the delivery of cardioplegic solutions may be impaired by anatomic and/or functional conditions, such as the development of transient aortic regurgitation during antegrade administration of cardioplegia or shunting through a foramen ovale during retrograde administration. In this study, the authors used a new method of cardioplegia administration, based on intraoperative contrast echocardiography, to detect on-line causes of inadequate cardioplegia delivery. METHODS: Forty patients with coronary artery disease and a competent aortic valve, who were treated consecutively, were enrolled in this study. Patients were monitored intraoperatively by transesophageal contrast echocardiography during cardioplegia delivery. Antegrade cardioplegia was administered into the aortic root following aortic occlusion in all patients. Twenty-two patients also received retrograde cardioplegia, administered through the right atrium. The echo-contrast agent consisted of a stable suspension of 5% human albumin microbubbles with a concentration of 4 x 10(8) microbubbles/ml and a diameter of 4 +/- 1 mu. RESULTS: Antegrade cardioplegia was not associated with aortic regurgitation in 23 of 40 (58%) patients. Seven patients (17%) had only mild aortic regurgitation, four patients (10%) had moderate regurgitation, and six (15%) had severe aortic regurgitation. The percent of myocardial opacification was 76.0 +/- 10.5 in the 23 patients who did not have aortic regurgitation, 76.0 +/- 17.0 in the 7 patients who had mild regurgitation, 52.5 +/- 18.1 in the 4 patients who had moderate regurgitation, and 48.5 +/- 18.3 in 6 patients who had severe aortic regurgitation (Kruskal-Wallis stat, 12.9; P < 0.005). Retrograde cardioplegia was not associated with right-to-left shunt in 11 of 22 patients (50%). In seven patients (32%), there was only a mild passage of contrast material to the left atrium. In the remaining four patients (18%), there was a moderate (one patient) to severe (three patients) right-to-left shunt at the level of the fossa ovalis. CONCLUSIONS: This study shows that incomplete myocardial distribution of cardioplegia, secondary to transient aortic valve incompetence or shunting through the foramen ovale, is not uncommon in patients undergoing coronary surgery.

Cardioplegic Solutions↗
PubMed1993

[Anterograde and retrograde cardioplegia in myocardial revascularization. An intraoperative contrast echographic study].

The aim of this study was to assess the distribution of antegrade and retrograde cardioplegia with intraoperative contrast echocardiography in patients undergoing coronary artery bypass grafting. Fifteen patients with chronic stable angina pectoris and severe coronary artery disease were studied. The severity of coronary artery disease was assessed at coronary angiography, using the Jeopardy Score System. The presence and the extent of collateral circulation was evaluated on the basis of preoperative coronary angiography and graded as: absent or poor; good or excellent. Coronary revascularization was carried out during extracorporeal circulation and myocardial protection was performed with antegrade (aortic root) and retrograde (right atrial) cardioplegia. The echo contrast agent was sterilely prepared 1 hour prior to surgery and consisted of a solution of sonicated 5% human albumin microbubbles. Two ml of sonicated albumin were injected along with antegrade cardioplegia and 4 ml with retrograde cardioplegia. The echocardiographic images were obtained with transesophageal echocardiography in the transgastric left ventricular short-axis view. Images were recorded on videotape for off-line planimetric measurement of percent myocardial opacification. Data were analyzed with the analysis of variance. Multiple comparisons were made with Student's paired t test and using Bonferroni's correction. Myocardial opacification was 58.9 +/- 12.9% during antegrade cardioplegia and 77.5 +/- 16.4% during retrograde cardioplegia (p = 0.003). This overall difference was mainly due to the impact of collateral circulation in the distribution of antegrade cardioplegia. Patients with absent or poor collateral circulation showed a lower degree of myocardial opacification than patients with good or excellent myocardial opacification (44.3 +/- 12.0% versus 64.2 +/- 8.6%; p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

[The identification of vital myocardium with the dopamine stimulation test: an intraoperative echocardiographic study].

The aim of this study was to detect by dopamine echocardiography dysfunctioning but viable myocardial segments. We have studied 19 patients with 3-vessel disease and chronic, stable angina pectoris. Patients were studied by intraoperative transesophageal echocardiography during coronary artery bypass surgery. The analysis of regional systolic function was performed utilizing the transgastric short-axis view at papillary muscle level and dividing the left ventricle in 8 segments, according to the recommendations of the American Society of Echocardiography. A total of 152 myocardial segments were analyzed. Percent systolic wall thickening was calculated in each segment at baseline (early after pericardiectomy), during dopamine infusion (5 mcg/kg/min) and 30 min after separation from cardiopulmonary bypass (after protamine administration). The administration of vasodilatory or inotropic drugs was avoided. The echocardiographic images were recorded on videotape and analyzed off-line by 2 independent observers. Segments showing at baseline percent systolic wall thickening < 30% were considered dysfunctional (134/152 = 88%). Eighty-four (63%) of these segments, increasing during dopamine infusion percent systolic wall thickening > 10% (from 12.9 +/- 3.5 to 20.7 +/- 5.4%; p < 0.05) were considered responder. On the other hand, 50 segments (37%) showing during dopamine an increment in percent systolic wall thickening < 10%, were considered non-responder. After coronary surgery, responder segments showed a significant increase in percent systolic wall thickening in comparison with baseline values (from 12.9 +/- 3.5 to 22.1 +/- 4.3%; p < 0.05). Segments non-responding to dopamine showed no significant changes in percent systolic wall thickening after myocardial revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1992

Echocardiographic analysis of dysfunctional and normal myocardial segments before and immediately after coronary artery bypass graft surgery.

Echocardiography has revealed evidence of "subnormal" regional contraction patterns that result from myocardial ischemia and are often accompanied by nonadjacent "hyperkinetic" regions. Whether these regions of hyperkinetic wall motion persist unchanged or revert to normal after coronary artery bypass graft (CABG) surgery has not been studied in humans. Using echocardiography, we evaluated both dysfunctional and normal myocardial regions for changes in segmental wall motion and percent of systolic wall thickening that occurred immediately after CABG surgery in 32 patients. Segmental wall motion analysis before CABG surgery in these patients revealed that 170 (66%) of 256 myocardial segments were subnormal, of which 115 (67%) improved and 102 (60%) returned to normal immediately after CABG surgery. Eleven myocardial segments that were hyperkinetic before CABG surgery returned to normal after CABG surgery. Preoperatively, 162 (63%) of 256 myocardial segments had systolic wall thickening less than 30%, which increased from 11.8% +/- 8.9% to 24.3% +/- 14.3% (mean +/- SD) (P less than 0.01) postoperatively. Conversely, a reverse trend was found when systolic wall thickening was greater than 30% before CABG surgery: thickening decreased from 46.2% +/- 13.8% to 33.4% +/- 14.8% after CABG surgery (P less than 0.01). Thus, we conclude that immediately after CABG surgery, there is a recovery of function in some myocardial segments and a reduction in function in others. Furthermore, we conclude that the semiquantitative assessment of percent of systolic wall thickening is a more reliable (consistent) echocardiographic index of myocardial function compared with the qualitative assessment of segmental wall motion immediately after CABG surgery.

Adult↗
PubMed1992

Reversal of left ventricular dysfunction early after coronary artery bypass grafting.

This study evaluated the early effect of coronary artery bypass grafting (CABG) on left ventricular systolic function. Intraoperative echocardiography was performed in 32 patients with coronary artery disease and chronic, stable angina pectoris. Left ventricular short-axis images at mid-papillary muscle level were videotaped at similar loading conditions shortly after pericardiotomy and 28 +/- 5 min after weaning from cardiopulmonary bypass. Inotropic or vasodilator administration was avoided or suspended at least 5 min before echocardiography. The left ventricle was divided off-line into 8 segments. The ejection fraction and percent systolic wall thickening (PSWT) were calculated pre- and post-CABG. A total of 256 myocardial segments were analyzed. Any segment showing a preoperative PSWT of less than 30% was considered dysfunctional, while segments with a PSWT of greater than 30% were considered normal. After surgery, the PSWT in 162 dysfunctional segments (63%) increased from 11.8 +/- 8.9 to 24.3 +/- 14.3% (p less than 0.001). Conversely, a reverse trend was found in the remaining 94 normal segments (37%) with a decreasing PSWT from 46.2 +/- 13.8 to 33.4 +/- 14.8% (p less than 0.001). Ejection fraction also increased from 47.2 +/- 3.5 to 58.5 +/- 18.9% (p less than 0.05). Thus, CABG is followed by an immediate recovery of systolic function in dysfunctional myocardial segments, while compensatory hyperfunction is reduced in normal segments. These results indicate that the post-CABG improvement in PSWT is due to redistribution of coronary blood flow, rather than to pharmacological or hormonal influences. Intraoperative echocardiography is a useful technique to monitor left ventricular function during surgery.

Adult↗
PubMed1991

Ventricular conduction defects and atrial fibrillation after coronary artery bypass grafting. Multivariate analysis of preoperative, intraoperative and postoperative variables.

Preoperative, intraoperative and postoperative variables, which might play a role in the development of ventricular conduction defects (VCD) and atrial fibrillation (AF) following coronary artery bypass grafting (CABG), were evaluated in 236 consecutive patients. VCD and AF developed postoperatively in 15.5% of patients: 4.5% had VCD (subgroup A), 11.0% had AF (subgroup B). In 84.5% of patients VCD and AF did not occur (subgroup C). Univariate analysis showed statistically significant differences between subgroups A and C with respect to: left main significant stenoses and number of diseased vessels. Bypass pump time and aortic cross-clamp time were significantly longer in subgroup B. Multivariate analysis showed a significantly greater incidence of left main disease and of right coronary artery occlusion associated with significant stenosis of the proximal left anterior descending artery in subgroup A. In subgroup B, the duration of aortic cross-clamp time was significantly higher. Ischaemic injury, with increasing duration of cardioplegic arrest, seems to play a key role in the development of AF. Nonhomogeneous cardioplegic delivery to critical areas of myocardium, and particularly to the specialized conducting system, may cause VCD after CABG.

Adult↗