Prospective evaluation of frequency and nature of transcranial high-intensity Doppler signals in prosthetic valve recipients

BACKGROUND AND AIM OF THE STUDY

In asymptomatic prosthetic valve recipients, high-intensity transient signals (HITS) observed with transcranial Doppler (TCD) are a phenomenon of obscure clinical relevance which nature has not yet been elucidated convincingly.

METHODS

Eighty-three patients without carotid disease, history of cerebrovascular accidents, and with negative preoperative TCD undergoing either valve replacement (mitral, n = 11; aortic, n = 56; mitral + aortic, n = 6; 40 mechanical prostheses, 29 biological prostheses, 10 homografts) or mitral repair (n = 10) were evaluated prospectively by means of TCD at discharge, three months and one year after surgery, to analyze the presence, incidence and characteristics of HITS. Furthermore, in 12 patients positive for HITS, TCD was repeated during a 30-min period of 100% O2 inhalation.

RESULTS

Twenty-five patients (30%) were positive for HITS at all postoperative controls, although no neurological symptoms were observed. Mechanical prostheses showed a significantly higher incidence of HITS (85%) than biological prostheses (10%, p <0.001), repaired mitral valves (0%, p <0.001) and homografts (0%, p <0.001). At multivariate analysis the presence of a mechanical prosthesis was the only significant predictor of detection of HITS after valve replacement. During O2 inhalation, a significant decrease in the number of HITS per hour (55 +/- 79 versus 22 +/- 31, p = 0.002) occurred, which returned to initial values when room-air breathing was resumed.

CONCLUSIONS

Prosthetic valve replacement, particularly when mechanical devices are used, is associated with the generation of HITS which persist throughout the follow up period, but remain clinically silent. The decrease of HITS during O2 inhalation strongly supports the hypothesis of the gaseous nature of such signals and confirms the validity of this method in helping to differentiate gaseous microemboli from solid microemboli in prosthetic valve recipients.

Cardiopulmonary exercise testing in patients with 21mm St. Jude Medical aortic prosthesis

BACKGROUND AND AIM OF THE STUDY

Small-sized prostheses may be associated with high transprosthetic gradients, particularly in patients with a body surface area (BSA) >1.70m2, affecting left ventricular mass regression, symptom improvement and long-term survival. However, the influence of such gradients on exercise tolerance has not been clearly defined. The study aim was to verify the utility of cardiopulmonary exercise testing (CPX) in detecting patient-prosthesis mismatch, and to identify the clinical and echocardiographic data that predict exercise tolerance at CPX in patients with a 21mm St. Jude Medical (SJM) aortic prosthesis.

METHODS

Twenty patients (one male, 19 females; mean age 66 +/- 9 years) with a 21 mm SJM prosthesis were evaluated by means of 2D echocardiography and CPX at 36 +/- 10 months after operation. Patients were divided into groups on the basis of a BSA of <1.70 m2 (group 1, n = 12) or > or =1.70 m2 (group 2, n = 8).

RESULTS

At echocardiography, left ventricular mass reduction was 16 +/- 10% versus 9 +/- 6% in groups 1 and 2, respectively, mean gradient (MG) was 15 +/- 6 versus 17 +/- 4 mmHg (p = NS), effective orifice area index (EOAi) 0.86 +/- 0.10 versus 0.79 +/- 0.09 cm2/m2 (p = 0.05). At CPX, group 2 patients showed a significantly lower exercise duration (p = 0.02), maximum workload (p = 0.02), peak O2 uptake (p = 0.01), anaerobic threshold (AT) (p = 0.03), ventilatory equivalent for CO2 at AT (p = 0.007), and O2 cost of work (p = 0.03). Group 1 patients showed a ventilatory origin for their effort dyspnea, while group 2 patients showed a significant circulatory component. At multivariate analysis, BSA, age, EOAi and MG were independent predictors of CPX results.

CONCLUSIONS

In patients with a 21 mm aortic SJM prosthesis and a BSA > or =1.70m2, CPX allows detection of patient-prosthesis mismatch, in terms of impaired exercise tolerance due to circulatory causes. CPX results can be anticipated on the basis of the patient's BSA, age, EOAi and MG. In these patients, technical solutions allowing implantation of a larger prosthesis should be considered whenever an active lifestyle is anticipated after aortic valve replacement.

Usefulness of CT colonography in patients with incomplete colonoscopy

OBJECTIVE

Our objective was to investigate the use of CT colonography in patients who have undergone incomplete colonoscopy.

CONCLUSION

CT colonography is effective in evaluating portions of the colon not seen during colonoscopy and may have an adjunctive role.

Combined mitral and tricuspid valve repair in acute infective endocarditis

Combined repair of the mitral and tricuspid valves involved with acute infective endocarditis was carried out in a 38-year-old drug addict. Mitral valve repair included vegetectomy, closure of posterior leaflet perforation, and posterior annuloplasty with a patch and a strip of glutaraldehyde-tanned autologous pericardium, respectively, while the tricuspid valve was reconstructed with the use of artificial chordae and valve bicuspidalization. At five months follow up the patient is asymptomatic, with echocardiographic evidence of only trivial mitral and tricuspid incompetence, and no signs of recurrent infection. This case report supports the use of valve reconstruction as a valuable option in patients in whom there is simultaneous involvement of the mitral and tricuspid valves with infective endocarditis.

Recurrent myxoma of the left ventricle. Case report and review of the literature

A 29-year-old female was found to have a left ventricular mass while in the 14th week of gestation. Seven years earlier she had undergone removal of a left ventricular myxoma. At re-operation, after elective interruption of pregnancy, a recurrent left ventricular myxoma was successfully excised. According to a review of the literature recurrence of an isolated, localized left ventricular myxoma has not been previously reported.

[Myocardial revascularization with arterial conduits: comparison of bilateral internal mammary artery and single internal mammary artery]

The use of bilateral internal mammary artery (BIMA) grafting for myocardial revascularization has been demonstrated to provide long-term benefits compared to revascularization using single left internal mammary artery (SIMA) and venous conduits. However, it is still controversial whether the use of BIMA is associated with a higher hospital mortality and morbidity. The present study retrospectively evaluated the possible advantages related to the use of BIMA at 3-year follow-up and whether the presence of operative risk factors in patients with BIMA could limit the application of the procedure in myocardial revascularization. We compared two groups of 100 patients matched for preoperative clinical characteristics, who underwent myocardial revascularization on the left coronary system with BIMA (93 males and 7 females, mean age 59 +/- 4 years) or with SIMA and venous conduits (86 males and 14 females, mean age 63 +/- 6 years). Hospital mortality rate was 2% in both groups, the use of BIMA being not a significant risk factor for hospital mortality and morbidity. The mean follow-up was 36 +/- 6 months for the BIMA group and 40 +/- 10 months for the SIMA group. At 3 years, there was no significant differences in the actuarial freedom from cardiac death (96 +/- 2% for BIMA vs 94 +/- 2% for SIMA patients), myocardial infarction (98 +/- 2 vs 97 +/- 2%), angina (93 +/- 2 vs 91 +/- 2%), symptomatic heart failure (92 +/- 3 vs 92 +/- 2%), coronary angioplasty/reoperation (96 +/- 2 vs 97 +/- 2% ), and total cardiac events (80 +/- 4 vs 76 +/- 4%). BIMA grafting was not an independent predictor of late cardiac events. In 66 patients who underwent a late angiographic or echo-Doppler study, the patency rate was 100% for the left mammary artery, 94% for the right mammary artery and 69% for venous conduits. In conclusion, myocardial revascularization with BIMA in situ is associated with low hospital mortality and morbidity, good clinical outcome and excellent patency rate at 3 years, with apparently no significant differences when compared to the use of SIMA and venous conduits. The low hospital mortality and morbidity and the satisfactory medium-term results in our opinion justify a more extensive use of BIMA in myocardial revascularization.

Aortobronchial fistula after coarctation repair and blunt chest trauma

A 34-year-old man had development of an aortobronchial fistula 17 years after patch aortoplasty for correction of aortic coarctation and 5 years after blunt chest trauma, an unusual combination of predisposing factors. The clinical presentation, characterized by dysphonia and recurrent hemoptysis, and the surgical findings suggested the posttraumatic origin of the fistula, which was successfully managed by aortic resection and graft interposition under simple aortic cross-clamping, associated with partial pulmonary lobectomy. When hemoptysis occurs in a patient with a history of an aortic thoracic procedure, the presence of an aortobronchial fistula should be suspected. Early diagnosis offers the only possibility of recovery through a lifesaving surgical procedure.

Late patency of recycled internal mammary artery: verification by Doppler echocardiography and coronary angiography

We report the case of a 57-year-old man who had presented with exertional angina early in 1997 and had subsequently undergone myocardial revascularization with the use of both internal mammary arteries. Two months after surgery, the patient was readmitted to the hospital with unstable angina. Coronary angiography revealed a 90% occlusion of the left internal mammary artery anastomosis, which was attached to the left anterior descending coronary artery. At reoperation, the left internal mammary artery was detached from the left anterior descending coronary artery, probed and injected with papaverine, checked for patency, and regrafted to the same coronary artery. Recycling of the left internal mammary artery was facilitated by the harvesting and routing technique that had been used during the previous operation. At the patient's 1-year follow-up visit, both Doppler echocardiography and coronary angiography showed patency of the recycled graft. We conclude that recycling of the left internal mammary artery is a safe and effective option in selected patients who require reoperation after myocardial revascularization.

Valve-related complications in elderly patients with biological and mechanical aortic valves

BACKGROUND

Controversy still exists about the choice of aortic prosthesis in elderly patients. This study investigates valve- and anticoagulant-related morbidity and mortality in elderly patients after aortic valve replacement (AVR) with a biologic (BP) or mechanical prosthesis (MP).

METHODS

Between 1981 and 1995, 355 consecutive patients aged 70 years or older (mean, 74+/-4 years; range, 70 to 87 years) underwent isolated AVR. There were 222 (63%) replacements with an MP and 133 (37%) with a BP. Mean follow-up was 3.7+/-2.8 years (range, 3 months to 15 years), with a total follow-up of 1,214 patient-years.

RESULTS

Hospital mortality was 7.6% (27 of 355), decreasing to 4.6% in the last 3 years. There were 55 late deaths, 33 in patients with MP and 22 in those with BP. At 10 years there was no significant difference between MP and BP recipients in the actuarial estimates of survival (51%+/-8% versus 33%+/-13%), freedom from valve-related death (82%+/-7% versus 72%+/-12%), and freedom from thromboembolism (84%+/-7% versus 94%+/-3%). In contrast, 10-year freedom from anticoagulant-related hemorrhages was 74%+/-8% for MP and 99%+/-1% for BP (p = 0.02). Only 1 structural deterioration occurred, in a patient with BP.

CONCLUSIONS

Satisfactory early results can be obtained in elderly patients after AVR with both MP and BP. The comparable low late survival in the two groups was predominantly influenced by non-valve-related deaths. A higher incidence of anticoagulant-related hemorrhages limits the use of MP in elderly patients. Thus, in this population, BP should be preferred not just on the basis of their expected longer durability, but mainly to avoid the risk of anticoagulant-related hemorrhages.

mmr, a Mycobacterium tuberculosis gene conferring resistance to small cationic dyes and inhibitors

The mmr gene, cloned from Mycobacterium tuberculosis, was shown to confer to Mycobacterium smegmatis resistance to tetraphenylphosphonium (TPP), erythromycin, ethidium bromide, acriflavine, safranin O, and pyronin Y. The gene appears to code for a protein containing four transmembrane domains. Studies of [3H]TPP intracellular accumulation strongly suggest that the resistance mediated by the Mmr protein involves active extrusion of TPP.

Transmyocardial holmium laser revascularization: feasibility of a thoracoscopic approach

OBJECTIVE

Creation of transmyocardial channels from the epicardium to the left ventricular cavity with the use of a laser is a modern approach in the treatment of patients with chronic ischemic heart disease unsuitable for coronary angioplasty or bypass grafting. We present the results of transmyocardial laser revascularization (TMLR) with a holmium laser as sole therapy in 22 patients operated on between November 1995 and February 1997.

METHODS

There were five females (23%) and 17 males (77%), with a mean age of 67+/-7 years (range 53-74 years). Previous myocardial revascularization had been performed in 77% of the patients. Pre-operatively, 12 patients (55%) were in angina class III and ten (45%) in class IV (mean 3.5+/-0.5); unstable angina was present in seven patients (32%). In 20 patients, TMLR was performed through a limited thoracotomy, while in two a thoracoscopic approach was used. Each patient received a mean of 33+/-8 channels in 27+/-13 min, while total operation lasted 130+/-28 min.

RESULTS

There were no hospital deaths and no major post-operative complications. Mean hospital stay was 7+/-3 days; the two patients undergoing thoracoscopic TMLR were discharged after 4 and 5 days, respectively. Two deaths were observed after 40 days and 4 months after TMLR, due to stroke and myocardial infarction. Mean follow-up of current survivors is 10+/-6 months (range 3-15 months), with seven patients followed for over 12 months. At last follow-up, mean angina class is 1.9+/-0.6 (P < 0.001). A significant increase in exercise tolerance and a reduction of the number of hospitalizations for angina were also observed. However, no significant changes in myocardial perfusion were observed.

CONCLUSIONS

The present study demonstrates that: (1) TMLR with a holmium laser yields clinical improvement in the majority of patients with severe angina unsuitable for conventional surgical treatment, (2) gratifying results in terms of improved anginal status and exercise tolerance are achieved, despite the lack of significant changes in myocardial perfusion at early follow-up and (3) TMLR through a thoracoscopic approach is a feasible procedure.

Quadricuspid aortic valve

A quadricuspid aortic valve was observed in a patient requiring aortic valve replacement because of severe aortic regurgitation, while in another it was accidentally detected by means of transesophageal echocardiography performed during coronary artery bypass grafting. This report discusses the apparent rarity of this malformation and stresses the need for periodical controls in patients known to have a quadricuspid aortic valve.

Aortic valve replacement for quadricuspid aortic valve incompetence

Quadricuspid aortic valve is an uncommon cause of aortic regurgitation. We report two patients who underwent aortic valve replacement because of severe aortic incompetence; the presence of a quadricuspid aortic valve was an accidental surgical finding. In one patient the aortic valve comprised two equal-sized larger cusps and two equal-sized smaller cusps, while in the other it comprised three cusps of similar size and a small accessory cusp between the right and non-coronary cusps. This report confirms the rarity of the disease and the fact that patients with quadricuspid aortic valves characterized by cusps of different sizes are more prone to develop progressive aortic incompetence because of unequal distribution of stresses on the valve. Therefore, such patients should undergo periodic, life-time echocardiographic assessment once this malformation is detected.

Enlargement of the aortic annulus with glutaraldehyde-fixed bovine pericardium during aortic valve replacement

BACKGROUND AND AIMS OF THE STUDY

Aortic valve replacement in patients with a small aortic annulus may represent a surgical challenge. We have evaluated a simplified technique to enlarge the aortic annulus which consists of extending the aortotomy incision to divide the commissure between the left and non-coronary cusps into the interleaflet triangle without opening the left atrium.

METHODS

This technique was used in 16 patients (15 women, one man; mean age 66 +/- 9 years) who underwent aortic valve replacement between August 1994 and February 1996. Aortic stenosis was the predominant valvular lesion. A mechanical prosthesis was implanted in 13 patients (81%) (21 mm in six, 23 mm in seven) while three received a bioprosthesis (21 mm in one, 23 mm in two). In all patients it was possible to insert a prosthesis at least one size larger than the original aortic annulus diameter.

RESULTS

There were no operative deaths and no late deaths. Mean follow up was 20 +/- 6 months (range: 12 to 30 months). Echocardiographic controls at 12 months postoperatively showed no evidence of periprosthetic leaks or mitral regurgitation. Comparison with preoperative data showed no significant variations of mean aortic diameter at the sinus level (30.7 +/- 2.2 mm versus 31.3 +/- 2.6 mm) or at the sinotubular junction (33.6 +/- 2.7 mm versus 34.3 +/- 2.9 mm) (p = NS). Significant reduction of left ventricular mass was observed (314 +/- 57 g versus 260 +/- 45 g; p < 0.001).

CONCLUSIONS

This technique is simple, reproducible and effective in allowing adequate enlargement of the aortic annulus and provides excellent clinical and hemodynamic results. Glutaraldehyde-fixed bovine pericardium used as a patch material showed no tendency to aneurysmal dilatation with progression of time at a maximum follow up of 30 months.

Operative technique for thoracoscopic transmyocardial laser revascularization

We describe herein the operative steps used to perform a transmyocardial laser revascularization by thoracoscopy. A special technique and specific equipment are required for the efficacy and safety of the procedure. Our preliminary results with this novel approach suggest that it could be a valid alternative to the thoracotomic procedure.

Early results of transmyocardial revascularization with a holmium laser

BACKGROUND

Transmyocardial laser revascularization (TMLR), a surgical technique designed to improve perfusion in the ischemic myocardium by creating transmural channels, has been performed thus far using a carbon dioxide laser, with apparently gratifying early results. We have investigated clinically TMLR using a holmium laser as sole therapy for patients with coronary artery disease that is not amenable to traditional treatment such as coronary artery bypass grafting or percutaneous transluminal coronary angioplasty.

METHODS

From November 1995 to December 1996, 16 patients underwent TMLR using a holmium laser. Their mean age was 68 +/- 6 years and 75% were men. Previous coronary artery bypass grafting or percutaneous transluminal coronary angioplasty had been performed in 81% and 31% of the patients, respectively. Before operation, their mean anginal class was 3.4 +/- 0.5 and their mean left ventricular ejection fraction was 0.49 +/- 0.06. Six patients had unstable angina.

RESULTS

There were no operative deaths. The mean duration of TMLR was 27 +/- 13 minutes and the mean duration of the entire operation was 120 +/- 40 minutes. There were no major postoperative complications and the mean hospital stay was 8 +/- 4 days. There were 2 late deaths, 1 that occurred 40 days after TMLR as a result of stroke and 1 that occurred 4 months after TMLR as a result of myocardial infarction. Current survivors have been followed up for a mean of 10 +/- 4 months (range, 3 to 15 months), with 7 patients followed up for 1 year. At last follow-up, the mean anginal class had decreased to 1.8 +/- 0.7 (p = 0.001) and the patients had increased exercise tolerance and a reduced number of hospitalizations. However, no statistically significant changes in the percentage of segments with fixed or reversible ischemia and no statistically significant differences in the viability scores of lased and nonlased segments were observed.

CONCLUSIONS

Transmyocardial laser revascularization using a holmium laser is a simple technique with low operative risk and low morbidity. Early results confirm that clinical improvement is obtained in most patients, although significant changes in myocardial perfusion are not evident in the short term.

Predicting outcome after myocardial revascularization in patients with left ventricular dysfunction

In order to identify the risk factors which could predict outcome after coronary artery bypass grafting in patients with left ventricular dysfunction, 80 consecutive patients with an ejection fraction < or = 30%, who underwent isolated coronary artery bypass grafting at the authors' centre between January 1994 and May 1996 were evaluated. Preoperatively, mean(s.d.) ejection fraction was 27.1(3.8)%, 56 patients (70%) had angina, and 56(70%) were in New York Heart Association (NYHA) functional class III or IV. There were five operative deaths, with a hospital mortality rate of 6.3%. Significant risk factors for hospital death were NYHA class IV, preoperative ventricular arrhythmias and left ventricular end-diastolic volume index > 110 ml/m2. At mean follow-up of 15(7) (range 6-30) months, there were six late deaths, five of which were from cardiac causes. Actuarial survival rate at 2 years was 82(5)% and freedom from cardiac death 84(5)%. Risk factors for overall mortality from cardiac causes were preoperative grade 2 mitral regurgitation, associated with left ventricular dilatation, and renal dysfunction (creatininaemia > or = 180 micromol/l). At follow-up, mean ejection fraction was 37.5(8.4)%, and the overall functional status had improved: 12 patients (18%) had angina and eight (12%) were in NYHA class III and IV. Myocardial revascularization in patients with left ventricular dysfunction can be performed with acceptably low operative risk, good survival rate at 2 years, and functional status improvement. Patients with extensive ventricular dilatation, associated with significant mitral regurgitation, have a lower life expectancy and less functional benefits from coronary artery bypass grafting. These patients are better treated by cardiac transplantation.

Ascending aorta dissection after aortic valve replacement

BACKGROUND AND AIMS OF THE STUDY

The surgical management of patients with aortic valve disease associated with ascending aortic dilatation is a controversial issue. Structural abnormalities of the aortic wall predispose to further aortic enlargement and possibly to ascending aortic dissection (AAD). Indications to concomitant replacement of aortic valve and ascending aorta have not yet been clearly defined.

METHODS

We reviewed eight consecutive patients (seven males and one female) among 2202 patients who underwent aortic valve replacement (AVR) between 1982 and 1996. These eight were subsequently reoperated on because of AAD, between November 1987 and November 1996. Indications for initial AVR were aortic regurgitation due to annular ectasia in five patients, combined aortic stenosis and regurgitation in two, and isolated aortic stenosis in one patient.

RESULTS

The interval between AVR and AAD ranged from four months to 10.5 years. Five patients presented with acute AAD, and three with chronic AAD. Retrospectively, four patients showed progressive increase in ascending aortic diameter after AVR, with a mean diameter of 72+/-9 mm at reoperation. Histological examination showed cystic medial necrosis in three patients, atherosclerotic degeneration in one patient, and normal aortic wall structure in one. There was one operative death due to low cardiac output; the hospital mortality rate was 13%. There were no late deaths and no major adverse events during a mean follow up of 5+/-3 years (range: 8 months to 10 years).

CONCLUSIONS

In patients with ascending aortic dilatation (> or = 55 mm diameter), AVR alone may not prevent progression of aortic root enlargement. In these patients, the ascending aorta should be concomitantly replaced. Following AVR, all patients with mildly or moderately dilated aortic root should be periodically controlled to detect signs of progression of aortic dilatation.

[Transmyocardial revascularization with a holmium laser: preliminary results]

BACKGROUND

Transmyocardial laser revascularization (TMLR) aims to improve perfusion of the ventricular wall via laser-created transmural channels. We present the results of TMLR with a holmium laser as sole therapy in patients with angina refractory to medical treatment and extensive coronary artery disease unsuitable for angioplasty or coronary artery by-pass grafting.

METHODS

From November 1995 to February 1997, twenty-two patients underwent isolated TMLR with a holmium laser. Five patients (23%) were female; the mean age was 67 +/- 7 years (range 53 to 74 years). Previous myocardial revascularization procedures had been performed in 17 patients (77%). Mean preoperative angina class was 3.4 +/- 0.5 and unstable angina was present in 7 patients (32%).

RESULTS

There were no hospital deaths. The only postoperative complications were transient supraventricular arrhythmias in 6 patients (27%). Each patient received a mean of 33 +/- 8 channels in 27 +/- 13 minutes. There were two late deaths, 40 days and 4 months after TMLR, due to stroke and myocardial infarction, respectively. Mean follow-up duration was 8 +/- 5 months (range 40 days-15 months). The mean number of hospitalizations due to angina fell from 4.9 +/- 1.5 in the 6 months before TMLR to 1.5 +/- 1.0 in the 6 months following surgery (p < 0.001). At follow-up, mean angina class had significantly improved (1.8 +/- 0.6, p < 0.001), as well as effort tolerance, which increased from a mean of 3.5 +/- 1.4 minutes to 5.1 +/- 1.7 minutes (p = 0.01). 201Tl SPECT at 3 and 6 months did not show any significant changes in the segmental perfusion of the lased and unlased areas.

CONCLUSIONS

TMLR with a holmium laser is a simple procedure with low operative mortality and morbidity. Short-term results confirm that clinical improvement is obtained in most patients, although this is not supported by significant changes in myocardial perfusion at short-term follow-up.

Transmyocardial laser revascularization using a thoracoscopic approach

Transmyocardial revascularization is a new technique aimed to improve perfusion of the ischemic myocardium by creating transmyocardial channels with a laser. This report demonstrates that transmyocardial revascularization with a holmium laser can be performed through a thoracoscopic approach.

Reoperation for prosthetic thrombosis and acute neurologic injury

Open-heart surgery in patients with recent cardiogenic embolic stroke represents a difficult management problem. We present a patient who developed thrombosis of a mitral tilting-disc prosthesis complicated by repeat cerebral embolic episodes that resulted in acute neurologic injury. We believe that in such patients the indication for reoperation must be individually evaluated but it is justified in young subjects, even in the presence of severe neurologic damage.