Isatuximab Monotherapy for Desensitization in Highly Sensitized Patients Awaiting Kidney Transplant

SIGNIFICANCE STATEMENT

There is no standardized desensitization regimen for kidney transplant candidates. CD38, expressed by plasma cells, could be targeted for desensitization to deplete plasma cells producing alloantibodies and donor-specific antibodies. Few studies and case reports are available regarding the use of CD38 antibodies for desensitization in patients awaiting kidney transplant. This study shows that isatuximab, a CD38-targeting therapy, was well tolerated in kidney transplant candidates, with a durable decrease in anti-HLA antibodies and partial desensitization activity. The short treatment period and long follow-up of this study allowed for the understanding of the mechanism and timing for any antibody rebound. Isatuximab could be further investigated as an option for adjunct therapy to existing desensitization for patients on the kidney transplant waitlist.

BACKGROUND

Patients with calculated panel reactive antibody (cPRA) ≥80.00%, particularly those with cPRA ≥99.90%, are considered highly sensitized and underserved by the Kidney Allocation System. Desensitization removes circulating reactive antibodies and/or suppresses antibody production to increase the chances of a negative crossmatch. CD38 is expressed highly on plasma cells, thus is a potential target for desensitization.

METHODS

This was an open-label single-arm phase 1/2 study investigating the safety, pharmacokinetics, and preliminary efficacy of isatuximab in patients awaiting kidney transplantation. There were two cohorts, cohorts A and B, which enrolled cPRA ≥99.90% and 80.00% to <99.90%, respectively.

RESULTS

Twenty-three patients (12 cohort A, 11 cohort B) received isatuximab 10 mg/kg weekly for 4 weeks then every 2 weeks for 8 weeks. Isatuximab was well tolerated with pharmacokinetic and pharmacodynamic profiles that indicated similar exposure to multiple myeloma trials. It resulted in decreases in CD38 + plasmablasts, plasma cells, and NK cells and significant reductions in HLA-specific IgG-producing memory B cells. Overall response rate, on the basis of a predefined composite desensitization end point, was 83.3% and 81.8% in cohorts A and B. Most responders had decreases in anti-HLA antibodies that were maintained for 26 weeks after the last dose. Overall, cPRA values were minimally affected, however, with only 9/23 patients (39%) having cPRA decreases to target levels. By study cutoff (median follow-up of 68 weeks), six patients received transplant offers, of which four were accepted.

CONCLUSIONS

In this open-label trial, isatuximab was well tolerated and resulted in a durable decrease in anti-HLA antibodies with partial desensitization activity.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04294459 .

Challenges and promise of targeting miRNA in rheumatic diseases: a computational approach to identify miRNA association with cell types, cytokines, and disease mechanisms

MicroRNAs (miRNAs) are small non-coding RNAs that alter the expression of target genes at the post-transcriptional level, influencing diverse outcomes in metabolism, cell differentiation, proliferation, cell survival, and cell death. Dysregulated miRNA expression is implicated in various rheumatic conditions, including ankylosing spondylitis (AS), gout, juvenile idiopathic arthritis (JIA), osteoarthritis (OA), psoriatic arthritis, rheumatoid arthritis (RA), Sjogren's syndrome, systemic lupus erythematosus (SLE) and systemic sclerosis. For this review, we used an open-source programming language- PowerShell, to scan the massive number of existing primary research publications on PubMed on miRNAs in these nine diseases to identify and count unique co-occurrences of individual miRNAs and the disease name. These counts were used to rank the top seven most relevant immuno-miRs based on their research volume in each rheumatic disease. Individual miRNAs were also screened for publication with the names of immune cells, cytokines, and pathological processes involved in rheumatic diseases. These occurrences were tabulated into matrices to identify hotspots for research relevance. Based on this information, we summarize the basic and clinical findings for the top three miRNAs - miR-146, miR-155, and miR-21 - whose relevance spans across multiple rheumatic diseases. Furthermore, we highlight some unique miRNAs for each disease and why some rheumatic conditions lack research in this emerging epigenetics field. With the overwhelming number of publications on miRNAs in rheumatic diseases, this review serves as a 'relevance finder' to guide researchers in selecting miRNAs based on the compiled existing knowledge of their involvement in disease pathogenesis. This approach applies to other disease contexts with the end goal of developing miRNA-based therapeutics.

Extracellular sulfatase-2 is overexpressed in rheumatoid arthritis and mediates the TNF-α-induced inflammatory activation of synovial fibroblasts

Extracellular sulfatase-2 (Sulf-2) influences receptor-ligand binding and subsequent signaling by chemokines and growth factors, yet Sulf-2 remains unexplored in inflammatory cytokine signaling in the context of rheumatoid arthritis (RA). In the present study, we characterized Sulf-2 expression in RA and investigated its potential role in TNF-α-induced synovial inflammation using primary human RA synovial fibroblasts (RASFs). Sulf-2 expression was significantly higher in serum and synovial tissues from patients with RA and in synovium and serum from hTNFtg mice. RNA sequencing analysis of TNF-α-stimulated RASFs showed that Sulf-2 siRNA modulated ~2500 genes compared to scrambled siRNA. Ingenuity Pathway Analysis of RNA sequencing data identified Sulf-2 as a primary target in fibroblasts and macrophages in RA. Western blot, ELISA, and qRT‒PCR analyses confirmed that Sulf-2 knockdown reduced the TNF-α-induced expression of ICAM1, VCAM1, CAD11, PDPN, CCL5, CX3CL1, CXCL10, and CXCL11. Signaling studies identified the protein kinase C-delta (PKCδ) and c-Jun N-terminal kinase (JNK) pathways as key in the TNF-α-mediated induction of proteins related to cellular adhesion and invasion. Knockdown of Sulf-2 abrogated TNF-α-induced RASF proliferation. Sulf-2 knockdown with siRNA and inhibition by OKN-007 suppressed the TNF-α-induced phosphorylation of PKCδ and JNK, thereby suppressing the nuclear translocation and DNA binding activity of the transcription factors AP-1 and NF-κBp65 in human RASFs. Interestingly, Sulf-2 expression positively correlated with the expression of TNF receptor 1, and coimmunoprecipitation assays demonstrated the binding of these two proteins, suggesting they exhibit crosstalk in TNF-α signaling. This study identified a novel role of Sulf-2 in TNF-α signaling and the activation of RA synoviocytes, providing the rationale for evaluating the therapeutic targeting of Sulf-2 in preclinical models of RA.

Interferon-stimulated GTPases in autoimmune and inflammatory diseases: promising role for the guanylate-binding protein (GBP) family

Human IFNs are secreted cytokines shown to stimulate the expression of over one thousand genes. These IFN-inducible genes primarily encode four major protein families, known as IFN-stimulated GTPases (ISGs), namely myxovirus-resistance proteins, guanylate-binding proteins (GBPs), p47 immunity-related GTPases and very large inducible guanosine triphosphate hydrolases (GTPases). These families respond specifically to type I or II IFNs and are well reported in coordinating immunity against some well known as well as newly discovered viral, bacterial and parasitic infections. A growing body of evidence highlights the potential contributory and regulatory roles of ISGs in dysregulated inflammation and autoimmune diseases. Our focus was to draw attention to studies that demonstrate increased expression of ISGs in the serum and affected tissues of patients with RA, SS, lupus, IBD and psoriasis. In this review, we analysed emerging literature describing the potential roles of ISGs, particularly the GBP family, in the context of autoimmunity. We also highlighted the promise and implications for therapeutically targeting IFNs and GBPs in the treatment of rheumatic diseases.

HLA-C: An Accomplice in Rheumatic Diseases

Human leukocyte antigen c (HLA-C) is a polymorphic membrane protein encoded by the HLA-C gene in the class I major histocompatibility complex. HLA-C plays an essential role in protection against cancer and viruses but has also been implicated in allograft rejection, preeclampsia, and autoimmune disease. This review summarizes reports and proposed mechanisms for the accessory role of HLA-C in rheumatic diseases. Historically, contributions of HLA-C to rheumatic diseases were eclipsed by the stronger association with HLA-DRB1 alleles containing the "shared epitope" with rheumatoid arthritis. Larger genetic association studies and more powerful analytical approaches have revealed independent associations of HLA-C with rheumatic disease-associated phenotypes, including development of anticitrullinated peptide antibodies. HLA-C functions by presenting antigens to T cells and by binding activatory and inhibitory receptors on natural killer (NK) cells, but the exact mechanisms by which the HLA-C locus contributes to autoimmunity are largely undefined. Studies have suggested that HLA-C and NK cell receptor polymorphisms may predict responsiveness to pharmacotherapy. Understanding the mechanisms of the role of HLA-C in rheumatic disease could uncover therapeutic targets or guide precision pharmacologic treatments.

Thrombus-targeted perfluorocarbon-containing liposomal bubbles for enhancement of ultrasonic thrombolysis: in vitro and in vivo study

BACKGROUND

External low-frequency ultrasound (USD) in combination with microbubbles has been reported to recanalize thrombotically occluded arteries in animal models.

OBJECTIVE

The purpose of this study was to examine the enhancing effect of thrombus-targeted bubble liposomes (BLs) developed for fresh thrombus imaging during ultrasonic thrombolysis.

METHODS

In vitro: after the administration of thrombus-targeted BLs or non-targeted BLs, the clot was exposed to low-frequency (27 kHz) USD for 5 min. In vivo: Rabbit iliofemoral arteries were thrombotically occluded, and an intravenous injection of either targeted BLs (n = 22) or non-targeted BLs (n = 22) was delivered. External low-frequency USD (low intensity, 1.4 W cm(-2) , to 12 arteries, and high intensity, 4.0 W cm(-2) , to 10 arteries, for both the targeted BL group and the non-targeted BL group) was applied to the thrombotically occluded arteries for 60 min. In another 10 rabbits, recombinant tissue-type plasminogen activator (rt-PA) was intravenously administered.

RESULTS

In vitro: the weight reduction rate of the clot with targeted BLs was significantly higher than that of the clot with non-targeted BLs. In vivo: TIMI grade 3 flow was present in a significantly higher number of rabbits with USD and targeted BLs than rabbits with USD and non-targeted BLs, or with rt-PA monotherapy. High-intensity USD exposure with targeted BLs achieved arterial recanalization in 90% of arteries, and the time to reperfusion was shorter than with rt-PA treatment (targeted BLs, 16.7 ± 5.0 min; rt-PA, 41.3 ± 14.4 min).

CONCLUSIONS

Thrombus-targeted BLs developed for USD thrombus imaging enhance ultrasonic disruption of thrombus both in vitro and in vivo.

Echocardiographic detection of Kaposi's sarcoma causing cardiac tamponade in a patient with acquired immunodeficiency syndrome

Pericardial effusions are common in patients with acquired immunodeficiency syndrome (AIDS). The differential diagnosis is diverse, and in most cases the etiology cannot be established. A cardiac tamponade was diagnosed in a 32-year-old male with AIDS and systemic Kaposi's sarcoma. Transthoracic echocardiography revealed a large pericardial effusion with right atrial collapse and a mobile multilobular mass at the apex protruding into pericardial space. Autopsy showed that this mass was Kaposi's sarcoma confined to the epicardial fat. This is the first case of cardiac Kaposi's sarcoma detected premortem by echocardiography.

Mitral annular calcification: a marker of severe coronary artery disease in patients under 65 years old

BACKGROUND

Mitral annular calcification has been associated with various systemic and cardiac diseases, with a higher prevalence in women and patients over 70. A possible association between mitral annular calcification and coronary artery disease has recently been suggested.

OBJECTIVE

To determine the prevalence of severe coronary artery disease in younger patients with mitral annular calcification.

METHODS

Consecutive patients aged <or= 65 years with and without mitral annular calcification as detected by echocardiography were identified from a prospective clinical database. Only patients with a coronary angiogram done within one year of their qualifying echocardiogram were analysed. Severe coronary artery disease was defined as >or= 70% stenosis of at least one major epicardial coronary artery.

PATIENTS

17 735 patients were screened. Of these, 6207 (35%) had mitral annular calcification and 885 (5%) were also <or= 65 years old; coronary angiography was done in 100 of the latter (64 men; 36 women), mainly for anginal symptoms or a positive stress test. A control group (n = 121; 88 men, 33 women) was identified from 2840 consecutive patients screened. There was no significant difference between the groups in patient characteristics, indication for angiography, or atherosclerotic risk factors.

RESULTS

Angiography showed a higher prevalence of severe coronary artery disease in patients with mitral annular calcification than in those without (88% v 68%, p = 0.0004), and a higher prevalence of left main coronary artery disease (14% v 4%, p = 0.009) and triple vessel disease (54% v 33%, p = 0.002). The positive predictive value of mitral annular calcification for finding severe coronary artery disease was 92%.

CONCLUSIONS

In patients aged <or= 65 years, mitral annular calcification is associated with an increased prevalence of severe obstructive coronary artery disease. It may serve as a useful echocardiographic marker for the presence of obstructive coronary artery disease, especially when associated with anginal symptoms.

Comparison of myocardial tissue Doppler with transmitral flow Doppler in left ventricular hypertrophy

We sought to determine the most useful echocardiographic measurements for assessment of diastolic function in patients with left ventricular hypertrophy (LVH) and normal systolic function. We compared myocardial Doppler velocities of the basal inferoposterior wall with mitral inflow pulsed wave Doppler velocities in 11 healthy volunteers (age, 36 +/- 6 years), 25 patients (age, 64 +/- 14 years) without LVH, and 37 patients (age, 67 +/- 14 years) with LVH and otherwise normal echocardiograms. The discriminatory measurements were myocardial A-wave duration (120 +/- 18 versus 98 +/- 20 and 92 +/- 12 ms, P <.0001), myocardial isovolumetric relaxation time (124 +/- 45 versus 95 +/- 48 and 78 +/- 25 ms, P =.0035), mitral A-wave velocity (0.98 +/- 0.37 versus 0.73 +/- 0.28 m/s and 0.61 +/- 0.22 m/s, P =.009), and mitral E-wave deceleration time (257 +/- 93 versus 201 +/- 85 ms and 184 +/- 83 ms, P =.015), which were significantly increased, and myocardial E-wave velocity (0.84 +/- 0.04 m/s versus 0.13 +/- 0.03 m/s and 0.14 +/- 0.03 m/s, P <.0001), which was significantly decreased, in patients with LVH compared with patients without LVH and normal volunteers, respectively. Left ventricular posterior wall thickness correlated with myocardial isovolumetric relaxation time (r = 0.52, P <.0001) and myocardial A-wave duration (r = 0.59, P <.0001), negatively with myocardial E wave (r = -0.43, P <.0001), and showed no correlation with mitral inflow parameters except mitral inflow A wave (r = 0.43, P =.002). On multivariate analysis using these variables, myocardial isovolumetric relaxation time (P =.0014) and A-wave duration (P =.001) were the only 2 variables that correlated with posterior wall thickness (multiple R = 0.71). In the presence of LVH and preserved left ventricular systolic function, myocardial relaxation time and velocities are more sensitive than mitral Doppler inflow parameters in detecting abnormal left ventricular relaxation.

Aortic root dilatation in patients with emphysema

BACKGROUND

Abdominal aortic aneurysms have been recognized to occur more frequently in patients with emphysema. However, the prevalence of aortic root dilatation in patients with emphysema and its relationship to risk factors for aortic enlargement have not been previously described.

METHODS

We studied 47 patients, past smokers (aged 67 +/- 6 years, 18 women) with severe emphysema diagnosed by a pulmonary function test and an ultrafast computed tomographic scan. Two-dimensional echocardiography was used to measure the aortic root at the aortic annulus, sinus of Valsalva, sinotubular junction and proximal part of the ascending aorta. Measured mean values were compared with published normal values and age- and sex-matched patients without emphysema. The relationship between aortic root size and cardiac risk factors (hypertension, hypercholesterolemia, and diabetes) was also examined.

RESULTS

In patients with emphysema the mean aortic root dimensions were significantly larger than normal values at each measured site (P <.0001) and those of patients without emphysema (P <.05 to.0001). A substantial percentage of patients with emphysema had larger sinus of Valsalva (43%) and proximal ascending aorta (59%) than the upper limit of normal. In the multivariable regression model, emphysema was a significant determinant of aortic root size at all measured sites and hypertension was associated with additional dilatation at the sinus of Valsalva, sinotubular junction, and proximal ascending aorta.

CONCLUSIONS

(1) In patients with emphysema the aortic root dimension is significantly larger than in patients without emphysema. (2) Systemic hypertension is associated with additional enlargement of the proximal ascending aorta, the sinus of Valsalva, and the sinotubular junction.

Association of mitral annulus calcification, aortic valve sclerosis and aortic root calcification with abnormal myocardial perfusion single photon emission tomography in subjects age < or =65 years old

OBJECTIVES

We examined the hypothesis that mitral annulus calcification (MAC), aortic valve sclerosis (AVS) and aortic root calcification (ARC) are associated with coronary artery disease (CAD) in subjects age < or =65 years.

BACKGROUND

Mitral annulus calcification, AVS and ARC frequently coexist and are associated with coronary risk factors and CAD in the elderly.

METHODS

We studied 338 subjects age < or =65 years who underwent evaluation of chest pain with myocardial perfusion single photon emission computed tomography (SPECT) and a two-dimensional transthoracic echocardiogram for other indications. The association of MAC, AVS and ARC with abnormal SPECT was evaluated by using chi-square analyses and logistic regression analyses.

RESULTS

Compared with no or one calcium deposit and no or one coronary risk factor other than diabetes, multiple (> or =2) calcium (or sclerosis) deposits with diabetes or multiple (> or =2) coronary risk factors were significantly associated with abnormal SPECT in women age < or =55 years old (odds ratio [OR], 20.00), in women age >55 years old (OR, 10.00) and in men age < or =55 years old (OR, 5.55). Multivariate analyses identified multiple calcium deposits as a significant predictor for an abnormal SPECT in women (p < 0.001), younger subjects age < or =55 years (p < 0.05) and the total group of subjects (p < 0.01).

CONCLUSIONS

When coronary risk factors are also taken into consideration, the presence of multiple calcium deposits in the mitral annulus, aortic valve or aortic root appears to be a marker of CAD in men < or =55 years old and women.

Myocardial Doppler tissue imaging: findings in inferior myocardial infarction and left ventricular hypertrophy--wall motion assessment

BACKGROUND

Because of the geometry of the basal inferior wall and its relation with the posterior medial papillary muscle, differentiating abnormal from normal basal inferior wall motion can be challenging.

METHODS

We performed pulsed wave Doppler echocardiography of the basal inferior wall and basal interventricular septum in 26 patients (63 +/- 14 years) with a normal echocardiogram, 33 patients (67 +/- 14 years) with inferior myocardial infarction (MI) associated with hypokinesis to dyskinesis of the basal inferior wall, and 38 patients (67 +/- 14 years) with left ventricular hypertrophy (LVH).

RESULTS

Systolic velocity was significantly lower in the basal interventricular septum (0.071 +/- 0.013 m/s versus 0.084 +/- 0.023 m/s) and basal inferior wall (0.075 +/- 0.014 m/s versus 0.085 +/- 0.019 m/s) in the MI group compared with the LVH group, and both were significantly lower compared with normal values at the interventricular septum (0.090 +/- 0.023 m/s, P <.001, analysis of variance) and basal inferior wall (0.095 +/- 0.014 m/s, P <.0001, analysis of variance). The sum of the systolic (S), early diastolic (E'), and late diastolic (A') velocities of 0.30 m/s at the basal inferior wall had 91%, 76%, and 84% sensitivity, specificity, and accuracy, respectively, for the differentiation of a normal wall from an infarcted basal inferior wall, and 76%, 73%, and 75% sensitivity, specificity, and accuracy, respectively, for the differentiation of a normal wall from a hypertrophied basal inferior wall. The sum of systolic and diastolic velocities of 0.25 m/s at the basal interventricular septum had 70%, 66%, and 68% sensitivity, specificity, and accuracy, respectively, for the differentiation of an infarcted from a hypertrophied basal interventricular septum. Mitral inflow early-filling wave deceleration time by pulsed wave Doppler was the most sensitive parameter for the differentiation of LVH from MI (P <.0001).

CONCLUSION

Doppler tissue imaging velocities of the basal inferior wall and basal interventricular septum may help differentiate normal from infarcted and hypertrophied myocardium.

There is synergism between high-intensity, low-frequency ultrasound and streptokinase but not with eptifibatide, heparin, and aspirin. Differential effects on fresh and aged blood clots. An in vitro study

OBJECTIVE

Ultrasound is emerging as a promising modality for recanalization of acutely thrombosed blood vessels, especially when associated with fibrinolytics. We assessed the efficacy of ultrasound combined with saline, heparin, eptifibatide, aspirin, and streptokinase in disruption of fresh as well as aged human blood clots, using an in vitro model.

METHODS

Blood clots from five donors, 2-4 or 48 hours old, were cut into 250-400 mg slices and immersed for 1, 15, or 30 min in 10 ml saline containing either heparin, eptifibatide, aspirin, streptokinase, or saline alone. Clots were then randomized to 10 s of 20 kHz ultrasound or immersion alone. After treatment, the percentage difference in weight was calculated.

RESULTS

Immersion of fresh clots without ultrasound in eptifibatide and heparin resulted in significantly more clot lysis than immersion in saline, aspirin, and streptokinase. Immersion of aged thrombi without ultrasound in heparin, eptifibatide, and aspirin had no additive effect over immersion in saline. Ultrasound enhanced clot disruption in all five solutions, in each immersion time and both in fresh and aged clots. Heparin and aspirin had no additive effect, compared with saline, on ultrasound disruption of both fresh and aged clots, whereas eptifibatide was less effective than saline. In contrast, streptokinase greatly enhanced disruption of both fresh (P=.004) and aged (P<.001) thrombi by ultrasound. The combinations of ultrasound with saline, heparin, eptifibatide, and aspirin were less effective on aged than fresh thrombi, whereas the combination of ultrasound with streptokinase was equally effective on fresh and aged thrombi.

CONCLUSIONS

Using a simple in vitro model, we found that the combination of streptokinase and low-frequency ultrasound had a synergistic effect on disruption of both fresh and aged blood clots. Further studies are needed to assess the role of heparin and antiplatelet agents in augmenting clot disruption by ultrasound in in vivo models of acute and subacute thrombosis.

Milrinone echocardiographic viability test: a pilot study

We assessed the utility of milrinone to predict recovery of function after surgical myocardial revascularization in patients with severe baseline left ventricular systolic dysfunction caused by coronary artery disease (CAD). Prediction of viable myocardial segments that will regain function after revascularization may help in the selection of patients who will benefit from coronary artery bypass graft surgery (CABG) as well as aid in the choice of target sites for coronary revascularization. We investigated 20 consecutive patients with CAD and left ventricular ejection fraction < or = 40% who had evidence of myocardial viability by either thallium scan or dobutamine viability test and were candidates for elective CABG. Left ventricular regional wall motion and global ejection fraction were assessed by transesophageal echocardiography in the operating room. Measurements were done before and 10 minutes after milrinone infusion, and immediately after CABG. Left ventricular wall motion score was derived by means of a 12-segment model. Functional improvement for each segment was defined as a wall motion change > 1. Baseline ejection fraction was 27% +/- 5% (mean +/- SD). Ejection fraction increased to 35% +/- 5% after milrinone infusion (P < .0001) and to 36% +/- 6% after CABG (P < .0001). Post-CABG ejection fraction was significantly correlated with postmilrinone ejection fraction (r = 0.65, P < .0001). Milrinone infusion resulted in augmentation of contraction in 98 of the 209 abnormal segments (wall motion score > or = 2); 91 (92.9%) of these improved after CABG. One hundred nine of the 111 segments that showed no improvement with milrinone did not improve after revascularization (98.2%). Seventy-three segments were akinetic or dyskinetic at baseline; 46 (63.0%) of these improved with milrinone. Improvement in regional wall motion after revascularization was detected in 84.8% of the segments that improved with milrinone versus only 3.7% of the segments that did not improve with milrinone. In patients with ischemic cardiomyopathy, improvement in left ventricular function (segmental wall motion and global ejection fraction) during milrinone infusion is highly predictive of improvement after CABG.

Arterial thrombus dissolution in vivo using a transducer-tipped, high-frequency ultrasound catheter and local low-dose urokinase delivery

PURPOSE

To examine the hypothesis that a transducer-tipped high-frequency ultrasound drug-delivery catheter may augment the thrombolytic effects of locally delivered low-dose urokinase and result in improved recanalization rates and reduced residual thrombotic burden.

METHODS

Thrombi were induced in situ bilaterally in 5- to 6-cm-long segments of the superficial femoral arteries in 9 dogs by intraluminal thermal damage and injection of thrombin. A transducer-tipped high-frequency local drug-delivery catheter was applied at 1.1 MHz and 0.6 W for 60 minutes to one superficial femoral artery segment, and an identical catheter with an inactivated ultrasound transducer was used to treat the contralateral control segment. Urokinase (5000 IU/kg) was delivered bilaterally into the thrombi during the treatment interval.

RESULTS

Angiography documented TIMI grade 2 or 3 flow in 9 (100%) segments in the ultrasound-treated group versus 6 (67%) of the controls (no ultrasound) (p = 0.058). Angiographically detected distal embolization was found in 2 ultrasound-treated segments compared with 5 controls (p = 0.02). Protruding or occlusive thrombi were seen angioscopically in 8 (89%) control segments but in only 1 (11%) of the ultrasound-treated arteries (p < 0.001). By histopathology, 7 (78%) segments in the control group had occlusive thrombi, whereas only 3 nonocclusive thrombi were found in the ultrasound-treatment group (p < 0.001).

CONCLUSIONS

Catheter-delivered high-frequency ultrasound and local low-dose urokinase infusion is efficacious for the treatment of acute thrombotic occlusions as evaluated by angiography, angioscopy, and histopathology.

Augmentation of in-vitro clot dissolution by low frequency high-intensity ultrasound combined with antiplatelet and antithrombotic drugs

BACKGROUND

Glycoprotein IIb/IIIa antagonists and heparin are increasingly used for treatment of acute coronary syndromes. There is no data on the effect of these drugs on clot dissolution when combined with low frequency high-intensity ultrasonic energy. We examined a possible additive effect of low frequency high-intensity ultrasound with an antithrombotic, an antiplatelet and a fibrinolytic agent alone or in combinations for in vitro blood clot dissolution.

METHODS

Human blood clots were incubated for 10', 15' and 30' in normal saline containing commonly used concentrations of heparin, tirofiban, t-PA and Optison (echocardiographic contrast agent) alone and in combinations. Clots were then randomly exposed to low frequency high-intensity ultrasound (27[emsp3 ]kHz) for 5 minutes. The percent difference in clot weight and the incremental effect of ultrasound energy were calculated.

RESULTS

The most significant additive effect of ultrasound energy was detected with the combination of tirofiban and heparin (39+/-2% augmentation after 10' of incubation, p<0.0001). The greatest magnitude of percent clot weight reduction was observed with ultrasound energy combined with either t-PA alone (72+/-1% after 30' incubation, p=0.0016) or with the combination of t-PA, tirofiban, heparin and Optison (68+/-4% after 30' incubation, p=0.015).

CONCLUSIONS

Application of low frequency high-intensity ultrasound has an additive effect to antiplatelet, antithrombotic and fibrinolytic drugs, specifically with the combination of tirofiban and heparin or with t-PA; this effect is observed after a short incubation period.

Noninvasive transthoracic low frequency ultrasound augments thrombolysis in a canine model of acute myocardial infarction--evaluation of the extent of ST-segment resolution

BACKGROUND

Recently it has been demonstrated that transcutaneous delivery of ultrasound combined with tissue plasminogen activator (tPA) is more effective than tPA alone in recanalizing acutely thrombosed canine coronary arteries. In the present study, we investigated the incidence of partial (> or =50%) and complete (> or =70%) ST-segment elevation resolution in the precordial leads of dogs with experimental acute myocardial infarction that were treated with tissue plasminogen activator (tPA) alone or in combination with noninvasive transcutaneous delivery of high-intensity low frequency (27[emsp3 ]kHz) ultrasound.

METHODS

Thrombotic coronary occlusions were induced in the midportion of left anterior descending (LAD) coronary artery by electrical injury in 24 dogs. All dogs were given intravenous heparin and tPA. Dogs were randomized to tPA alone (n=12) or combined tPA and adjunctive transcutaneous ultrasound (US) delivery (n=12). Electrocardiograms were recorded at 1) baseline, 2) after coronary occlusion just before initiation of therapy, 3) when coronary angiography showed recanalization of the coronary artery (or at 90 minutes after initiation of therapy if reperfusion did not occur before then) and 4) 90 minutes later. ST amplitude was measured in all 6 precordial leads.

RESULTS

ST-segment amplitude at baseline was comparable between the tPA and the US group. Before initiation of therapy, sum of ST-segment elevation tended to be higher in the US group. At reperfusion and 90 minutes thereafter, sum of ST-segment amplitude tended to be smaller for the US group than in the tPA group (p<0.001 for the time effect; p=0.118 for the time x group interaction). Up to 90 minutes after initiation of therapy >/=50% resolution of the sum of precordial ST elevation was detected in 7 out of 11 dogs (63.6%) in the tPA group versus 10 out of 11 dogs (90.9%) in the US group. Ninety minutes thereafter, 3 out of 7 dogs in the tPA group (42.9%) versus 9 of 11 dogs in the US group (81.8%) had >/=50% resolution of the sum of precordial ST elevation.

CONCLUSIONS

The combination of tPA with noninvasive transcutaneous delivery of low frequency high-intensity ultrasound resulted in greater resolution of ST-segment elevation when reperfusion occurs and 90 minutes thereafter, as well as a higher rate of epicardial coronary artery reperfusion.

Ultrasound as treatment for coronary artery disease

Therapeutic ultrasound is already established in the treatment of diverse surgical conditions, such as cataract, liver cancer, and stones, without danger to healthy tissue. Clinical trials of catheter-delivered, high energy, low frequency (kHz) ultrasound undertaken over the last decade have demonstrated the safety of ultrasound in the treatment of peripheral and coronary artery disease, and have identified a number of indications in which it may be particularly advantageous. The dispersal of thrombus, the recanalization of chronic total occlusions, and the favorable modification of the distensibility of small, atherosclerotic vessels are three promising areas. The authors review developments in these fields.

The use of transducer-tipped ultrasound catheter for recanalization of thrombotic arterial occlusions

Ultrasound energy is currently being used and intensively investigated for recanalization of thrombotically occluded arteries. The ultrasonic energy is mainly applied either by a transcutaneous approach or by a percutaneous approach through a catheter with an external ultrasound transducer. Catheter-delivered transducer-tipped ultrasound thrombolysis is a new and innovative method. In this article we summarize the current available data on the use of this new type of catheter and discuss future directions and clinical applications.

Noninvasive transcutaneous low frequency ultrasound enhances thrombolysis in peripheral and coronary arteries

Previous studies have shown that external ultrasound with low frequencies and high intensities can enhance thrombolytic drug-induced clot dissolution during in vitro experiments. In this series of studies, we evaluated the efficacy of peripheral and coronary thrombolysis in vivo in animals by using noninvasive transcutaneous ultrasound combined with thrombolytic drugs (streptokinase and tPA) and/or microbubbles agents (dodecafluoropentane [DDFP] and perfluorocarbon-exposed sonicated dextrose albumin [PESDA]). Thrombotic occlusions were induced in 74 rabbit iliofemoral arteries and 24 canine left anterior descending (LAD) coronary arteries in this in vivo study. By using the combination of transcutaneous ultrasound and streptokinase, the angiographic patency rate in rabbit iliofemoral arteries was higher (56%-100%) than with ultrasound (6%; P < or = 0.0036) and streptokinase alone (6%; P < or = 0.0012). Also, with transcutaneous ultrasound and microbubbles, the angiographic patency rates were 76%-100% as compared with ultrasound alone (0%, P < or = 0.0003) or microbubbles alone (9%, P < or = 0.0001). In the canine study of acute myocardial infarction, thrombolysis in myocardial infarction (TIMI) grade flow at 90 minutes in the tPA alone group was 0.92 +/- 1.4 as compared with 2.42 +/- 1.9 in the tPA plus transthoracic ultrasound group (P = 0.006). There was much improved reperfusion with tPA plus ultrasound as compared with tPA alone. In vivo animal studies demonstrate that noninvasive transcutaneous ultrasound can greatly enhance the effect of clot dissolution with thrombolytic drugs and/or microbubbles, and has the potential for clinical application as an adjunctive method to improve arterial thrombolysis.

The effects of streptokinase and hydroxyethyl starch on in vitro clot disruption by ultrasound

BACKGROUND

In vitro studies showed that low-frequency ultrasound (US) causes blood clot dissolution. This effect is augmented with thrombolytics, microbubbles and microparticles. However, in animal models of transcutaneous delivery, US alone is not effective, probably due to attenuation of US energy by overlying skin. When combined with thrombolytics or microbubbles, transcutaneous US is highly effective.

PURPOSE

To assess the synergistic effect of low-intensity low-frequency US and saline, hydroxyethyl starch (HAES) (a non-gas filled microparticle containing solution), streptokinase (STK), and their combination on blood clot disruption.

METHODS

Human blood clots from 4 healthy donors, 2-4 hours old, were immersed for 0, 15, or 30 min in 37 degrees C in 10 ml of the above-mentioned solutions, and then were randomized to 10 sec of 20 kHz US or no US. The % difference in weight was calculated.

RESULTS

Immersion for 30 min without US resulted in 13.8 +/- 1.2% clot lysis in saline, and 22.0 +/- 1.3%, 21.7 +/- 2.1%, and 23.2 +/- 1.9% in STK, HAES, and STK + HAES, respectively (p = 0.002). US augmented clot lysis in all groups and at all time points. With low-intensity US, HAES was not better than saline. However, the combination of HAES + STK with US resulted in larger clot disruption at 15 sec incubation time (46.7 +/- 3.2%) than with saline (29.6 +/- 2.1%), HAES (29.6 +/- 2.5%), and STK (32.8 +/- 3.6%) (p < 0.001).

CONCLUSION

low-frequency, low-intensity US combined with HAES and STK resulted in greater clot disruption at short incubation times. This combination may assist in achieving faster reperfusion in in vivo models.

Coronary remodeling of proximal and distal stenotic atherosclerotic plaques within the same artery by intravascular ultrasound study

The aim of this intravascular ultrasound study was to compare the type and the degree of vessel remodeling in proximal and distal de novo lesions within the same coronary artery in patients with stable angina pectoris. Seventy-six de novo coronary artery lesions in 38 coronary arteries of 38 patients were imaged by intravascular ultrasound. The vessel area (VA) within the external elastic lamina and the lumen area (LA) were measured, and the wall area (VA-LA) was calculated at the lesion site, and the proximal and distal reference sites. The VA ratio was defined as (lesion VA/average of the proximal and distal reference VAs) to represent the degree of vessel remodeling. The proximal coronary segments showed compensatory enlargement more often (68% vs 29%, p < 0.01) than the distal segments, and the VA ratio at the lesion site was significantly larger (1.1 +/- 0.3 vs 1.0 +/- 0.2, p <0 .01) in proximal segments than in distal segments. The type of coronary remodeling was discordant in 61% and concordant in only 39% of coronary arteries between the proximal and distal segments. The type of coronary remodeling of proximal and distal coronary lesions was inhomogeneous, even within the same vessel. Proximal coronary segments showed more prominent compensatory enlargement than distal segments, which have a similar degree of luminal narrowings.

Influence of ejection fraction and valvular regurgitation on the accuracy of aortic valve area determination

OBJECTIVE

To examine the influence of left ventricular dysfunction, aortic regurgitation, and mitral regurgitation on commonly used methods for aortic valve area (AVA) determination.

BACKGROUND

Each method for AVA determination has its inherent limitations.

METHODS

AVA determinations by transesophageal echocardiography (TEE) using planimetry, transthoracic echocardiography (TTE) with application of the continuity equation, and cardiac catheterization applying the Gorlin formula were performed in 74 patients with aortic stenosis. The severity of the aortic stenosis was defined by consensus of at least two methods. Over- or underestimation of AVA associated with ejection fraction, aortic regurgitation, mitral regurgitation, or severity of the aortic stenosis for each method in relation to the other two methods was assessed.

RESULTS

Mean AVAs were 1.05 +/- 0.51 by TEE, 1.06 +/- 0.51 by TTE, and 1.08 +/- 0.53 by cardiac catheterization. An overestimation of the severity of the aortic stenosis by the Gorlin formula in patients with moderate-to-severe aortic regurgitation as compared to TEE-derived data was found (P = 0.014). A similar trend of overestimation by catheterization in comparison with the TTE data was found. In the context of moderate-to-severe mitral regurgitation, AVA determination by TTE overestimated the degree of aortic stenosis as compared to TEE (P = 0.011) and cardiac catheterization (P = 0.023).

CONCLUSIONS

Overall mean AVA did not differ between methods, suggesting that these three methods are equally accurate in a nonselected clinical patient group. However, in the presence of significant aortic regurgitation, the two echocardiographic methods appear more accurate. Our observation of an overestimation of the severity of aortic stenosis by TTE in the presence of moderate-to-severe mitral regurgitation indicates that this possibility should be accounted for in clinical decisions based on TTE determinations of AVA.

Pacing stress echocardiography: an alternative to pharmacologic stress testing

OBJECTIVES

We sought to evaluate the diagnostic accuracy and feasibility of bedside pacing stress echocardiography (PASE) as a potential substitute for pharmacologic stress echocardiography in patients admitted to the hospital with new-onset chest pain or worsening angina pectoris.

BACKGROUND

Accurate and rapid noninvasive identification and evaluation of the extent of coronary artery disease (CAD) is essential for optimal management of these patients.

METHODS

Bedside transthoracic stress echocardiography was performed in 54 consecutive patients admitted to a community hospital with new-onset chest pain, after acute myocardial infarction had been excluded. We used 10F transesophageal pacing catheters and a rapid and modified pacing protocol. The PASE results were validated in all patients by coronary angiography performed within 24 h of the test. Significant CAD was defined as > or =75% stenosis in at least one major epicardial coronary artery.

RESULTS

The sensitivity of PASE for identifying patients with significant CAD was 95%, specificity was 87% and accuracy was 92%. The extent of significant CAD (single- or multivessel disease) was highly concordant with coronary angiography (kappa = 0.73, p<0.001). Pacing stress echocardiography was well tolerated, and only 4% of the patients had minor adverse events. The mean rate-pressure product at peak pacing was 22,313+/-5,357 beats/min per mm Hg, and heart rate >85% of the age-predicted target was achieved in 94% of patients. The average duration of the bedside PASE test, including image interpretation, was 38+/-6 min.

CONCLUSIONS

Bedside PASE is rapid, tolerable and accurate for identification of significant CAD in patients admitted to the hospital with new-onset chest pain or worsening angina pectoris.

Clinical and electrocardiographic variables associated with increased risk of ventricular septal defect in acute anterior myocardial infarction

It is unknown whether the risk factors associated with the development of ventricular septal defect (VSD) after acute myocardial infarction (MI) remain the same when thrombolytic therapy is used, nor have specific electrocardiographic patterns of acute MI associated with the development of VSD been identified. Our study population included patients with an anterior MI enrolled in the GUSTO-I study. Baseline clinical data were collected prospectively for all patients. Patients in whom VSD was suspected by the local investigators at each site were evaluated retrospectively. Baseline clinical and electrocardiographic variables were compared between 2 groups: 10,847 patients without VSD (99.6%) and 48 patients with confirmed VSD (0.4%). Multivariate analysis showed the following clinical variables to be independent predictors of VSD: age (odds ratio [OR] 2.19, 95% confidence intervals [CI] 1.62 to 2.98; p <0.001), female gender (OR 5.07, 95% CI 2.70 to 9.98; p <0.001), and lack of previous angina (OR 2.11, 95% CI 1.12 to 4.29; p = 0.021). Two electrocardiographic variables predicted acute VSD: the magnitude of ST deviation in lead III (OR 1.55, 95% CI 1.12 to 2.21; p = 0.007) and in lead V(2) (p <0.001). However, the relation between the ST amplitude in lead V(2) and the risk for VSD was nonlinear. In patients with anterior MI who underwent thrombolysis, the risk factors for VSD were age, female gender, and lack of previous angina. Previous infarction was not a risk factor. Less ST-segment depression in lead III was a predictor of VSD.

Transthoracic stress echocardiography with transesophageal atrial pacing for bedside evaluation of inducible myocardial ischemia in patients with new-onset chest pain

To date, there are no data on the feasibility and accuracy of bedside pacing stress echocardiography in patients admitted to the hospital with new-onset chest pain or unstable angina. We evaluated the feasibility of pacing stress echocardiography and examined its correlation with myocardial perfusion stress scintigraphy (rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion single-photon emission computerized tomography) performed within 24 hours of the pacing stress echocardiography test. We studied 70 consecutive patients after acute myocardial infarction had been excluded. The bedside pacing stress echocardiography test was performed with 10Fr transesophageal pacing catheters. We found pacing stress echocardiography to be feasible and safe (3% minor adverse event rate) at the patients' bedside. Target heart rate of >85% of the age-predicted heart rate was achieved in 96% of patients, and the mean rate-pressure product was 22,644 +/- 4,520 beats/min/mm Hg. The mean duration of the bedside pacing stress echocardiography test including technical preparations and image interpretation was 41 +/- 7 minutes. Pacing stress echocardiography and myocardial perfusion stress scintigraphy correlated well for identification or exclusion of inducible myocardial ischemia in 63 of 70 patients (90%) (kappa 0.81, p <0.001). The extent of inducible myocardial ischemia by vascular territories correlated with myocardial perfusion stress scintigraphy in 52 of 70 patients (74%) (kappa 0.6, p <0.001). We conclude that bedside pacing stress echocardiography is feasible and safe, and highly correlates with myocardial perfusion stress scintigraphy for identifying inducible myocardial ischemia in patients with new onset of chest pain or unstable angina.

Microparticle-containing oncotic solutions augment in-vitro clot disruption by ultrasound

Echocardiographic contrast agents enhance blood clot disruption by ultrasound. It has been suggested that the microbubbles add nuclei for the enhancement of cavitation by ultrasound. However, microbubbles are rapidly destroyed by the ultrasound energy. We assessed whether non-gas filled colloidal solutions (hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides) will facilitate clot disruption by ultrasound. In two separate experiments human blood clots, 200-400 mg in weight, were weighed and then immersed for 15 seconds in 10 ml normal saline solution containing 0%, 0.1%, 1%, 2%, and 5% of hyperoncotic medium molecular hydroxyethyl starch or 0%, 0.035%, 0.175%, 0.35%, and 0.7% degraded gelatin polypeptides. Clots were randomized to 10 seconds 20 kHz ultrasound or immersion without ultrasound. After treatment, the clots were reweighed, and the percent difference in weight was calculated. Non-gas filled microparticle-containing solutions such as hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides significantly augmented blood clot disruption by ultrasound. The effect is dependent on the colloidal solution concentration with maximal effect achieved with 1% hyperoncotic medium molecular hydroxyethyl starch and 0.35% degraded gelatin polypeptides.

Noninvasive, transthoracic, low-frequency ultrasound augments thrombolysis in a canine model of acute myocardial infarction

BACKGROUND

Limitations of coronary thrombolysis include the time to reperfusion, patency rate, and bleeding. We evaluated the use of noninvasive transcutaneous ultrasound to augment coronary thrombolysis.

METHODS AND RESULTS

In 24 dogs, a thrombotic occlusion of the left anterior descending coronary artery was induced and documented by 12-lead ECG and coronary angiography. After >/=60 minutes of occlusion, tissue-type plasminogen activator (t-PA; 1.42 mg/kg) was given intravenously over 90 minutes. A total of 12 of the 24 dogs had concomitant transcutaneous application of low-frequency ultrasound (27 kHz) over the chest. At 90 minutes, the mean TIMI grade flow in the t-PA alone group was 0.92+/-1.4 compared with 2. 42+/-1.9 in the t-PA plus ultrasound group (P=0.006). TIMI 2 to 3 flow was present in 4 of 12 cases receiving t-PA alone compared with 10 of 12 cases receiving t-PA plus ultrasound (P=0.003). At 180 minutes, mean TIMI grade flow was 0.75+/-1.4 in the t-PA alone group versus 2.58+/-0.9 in the t-PA plus ultrasound group (P=0.001). Pathological examination confirmed the angiographic patency rate and did not reveal injury secondary to ultrasound in the skin, soft tissues, heart, or lungs.

CONCLUSIONS

In vivo, the noninvasive transthoracic application of low-frequency ultrasound (1) greatly augments the efficacy of t-PA-mediated thrombolysis, (2) seems safe, and (3) has substantial potential as a noninvasive adjunct to improve coronary patency without increasing the risk of bleeding.

Metastatic pancreatic adenocarcinoma to the heart diagnosed antemortem

Pancreatic tumors frequently metastasize widely, though it is rare to diagnose pancreatic cardiac metastases in the antemortem state. We report an unusual case of metastatic pancreatic adenocarcinoma to the right atrium. Transesophageal echocardiography showed that the tumor was attached to the superior aspect of the right atrium, prolapsing through and obstructing the tricuspid valve in diastole and retracting back into the right atrium during systole. The tumor was excised, and histologic examination confirmed the presence of moderately differentiated adenocarcinoma with a papillary architectural pattern and with desmoplastic stroma, features comparable to the original primary pancreatic neoplasm.

Usefulness of left ventricular mass in predicting recovery of left ventricular systolic function in patients with symptomatic idiopathic dilated cardiomyopathy

Prognosis of idiopathic dilated cardiomyopathy (IDC) is variable. We determined the prognostic value of left ventricular (LV) mass and systolic and diastolic function in patients with IDC of <12 months duration. Clinical and echocardiographic assessment was performed at baseline and at 8+/-6 months follow-up in 25 patients (47+/-13 years) with IDC and an LV ejection fraction (LVEF1) of <40% (22+/-7%). Based on a follow-up LVEF (LVEF2) of < or >40%, patients were divided into unimproved (n = 13, LVEF2 = 21+/-9%) and improved groups (n = 12, LVEF2 = 51+/-11%). There was no difference in the LVEF1 (22+/-8% vs. 22+/-6%), LV end-systolic (5.7+/-0.8 vs. 5.8+/-0.9 cm) or end-diastolic (6.5+/-0.6 vs. 6.6+/-0.9 cm) dimension, wall stress (102+/-26 vs 99+/-28 g/cm2), end-systolic (1.7+/-0.3 vs. 1.8+/-0.2) or end-diastolic (1.7+/-0.3 vs. 1.6+/-0.1) sphericity, dp/dt (582+/-163 vs. 678+/-222 mm Hg/s), or right ventricular fractional shortening (20+/-9% vs. 27+/-7%, p = 0.06) in unimproved and improved groups. LV mass was lower (1.00+/-0.21 vs. 1.38+/-0.27 g/ml, p = 0007) and mitral inflow E-wave deceleration time shorter (97+/-42 vs. 164+/-58 ms, p = 0007) in the unimproved versus the improved group. On Pearson correlation analysis, LV mass (r = 0.62, p = 0.001), deceleration time (r = 0.68, p = 0.0002), wall motion score index (r = -0.47, p = 02), and dp/dt (r = 0.52, p = 03) were the significant predictors of LVEF2. There was correlation between LV mass (grams per milliliter) and deceleration time (r = 0.61, p = 0.001). During follow-up, death occurred in 1, and readmission for worsening heart failure in 4 patients in the unimproved group versus no hospitalization in the improved group. Thus, in patients with recent onset IDC, LV mass and diastolic function determine late outcome.

Regression of hypertrophy after Carpentier-Edwards pericardial aortic valve replacement

BACKGROUND

The purpose of this study was to determine whether significant regression of left ventricular hypertrophy is seen after implantation of small sizes (19 to 23 mm) of the Carpentier-Edwards (CE) pericardial valve, a stented pericardial valve.

METHODS

Echocardiograms and electrocardiograms (ECGs) were performed at least 1 year after surgery (mean 18 months) in patients with 19-, 21-, and 23-mm CE pericardial aortic valves and compared with preoperative echocardiograms and ECGs.

RESULTS

A total of 41 patients, mean age 79 +/- 9 years (range 46 to 93 years), were studied, including 7 19-mm, 22 21-mm, and 12 23-mm patients. The mean postoperative gradient was 22 +/- 7 mm Hg for 19-mm valves, 18 +/- 5 mm Hg for 21-mm valves, and 16 +/- 4 mm Hg for 23-mm valves. The postoperative valve areas were 1.1 +/- 0.3 cm2 for the 19-mm, 1.3 +/- 0.3 cm2 for the 21-mm, and 1.5 +/- 0.4 cm2 for the 23-mm valves. Left ventricular end diastolic diameter, end systolic diameter, septal thickness, and posterior wall thickness all decreased significantly (p <0.05) postoperatively. The proportion of patients with significant left ventricular hypertrophy on ECG decreased from 63% to 47% (p = 0.001). Left ventricular mass decreased significantly by echocardiography from 265 g preoperatively to 208 g postoperatively (p = 0.004). Left ventricular mass decreased for each valve size, and the greatest absolute reduction in mass occurred in the 19-mm valve recipients.

CONCLUSIONS

Implantation of the 19-, 21-, and 23-mm CE pericardial valves results in significant reductions in left ventricular mass. These findings suggest that stented pericardial valves can be used in the small aortic root without the need for aortic root enlargement procedures.

Ultrasound has synergistic effects in vitro with tirofiban and heparin for thrombus dissolution

Previous studies have shown synergism between ultrasound and thrombolytic agents or microbubbles on blood clot dissolution. It has not been investigated whether heparin or glycoprotein IIb/IIIa blockers enhance clot lysis by ultrasound. We compared the blood clot dissolution effect of saline, heparin, tissue plasminogen activator (tPA), tirofiban, and an echocardiographic contrast media (Optison) without and with ultrasound application. Human blood clots from four donors, 2 to 4 hours old, were cut into 200- to 400-mg sections, weighed, and immersed for 2 minutes in 1 L of normal saline 0.9% solution containing either heparin 1000 U, tirofiban 150 microg, tPA 20 mg, Optison 0.5 mL, or normal saline alone. Clots were randomized to 2 minutes ultrasound application or immersion alone without ultrasound. Ultrasound was applied with a 19.5 KHz catheter. After treatment, the clots were weighed, and the absolute and percent difference in weight was calculated. Immersion in heparin, tirofiban, and tPA without ultrasound did not augment clot disruption relative to normal saline alone. Immersion in Optison (p = 0.07) tended to result in less lysis than saline alone. Ultrasound enhanced clot dissolution compared to immersion alone with: saline (48.1+/-15.3% vs. 26.0+/-13.8%, p<0.0000002); heparin (60.8+/-17.5% vs. 30.8+/-15.1%, p = 0.000001); tirofiban (61.8+/-13.6% vs. 30.1+/-12.2%, p<0.0000001); tPA (53.1+/-15.3% vs. 30.2+/-11.5%, p<0.000002); and Optison (47.8+/-16.0% vs. 18.4+/-11.5%, p<0.0000001). The combination of tirofiban with ultrasound, as well as heparin with ultrasound, was associated with a significant augmentation of clot dissolution compared with the saline plus ultrasound group (p = 0.002, 0.013, respectively). Ultrasound with tPA or with Optison had no significant augmentation of clot dissolution over the ultrasound + saline effect. This in vitro study of catheter-delivered high-intensity low-frequency ultrasound demonstrates that: (1) tirofiban and heparin, as well as perfluorocarbon microbubbles, augment clot dissolution by ultrasound; (2) augmentation of clot dissolution is evident even after only brief exposure of ultrasound and the drug studied.

Echocardiographic and pathologic features of explanted Hancock and Carpentier-Edwards bioprosthetic valves in the mitral position

Modes of failure of Hancock and Carpentier-Edwards (C-E) porcine bioprosthetic valves placed in the mitral position are not completely understood. We reviewed transesophageal echocardiographic (n = 19) and pathologic features of failed Hancock (n = 22) and C-E (n = 8) porcine mitral valves in 30 patients (mean age 70 +/- 13 years). Age at implantation (59 +/- 14 vs 58 +/-14 years, p = 0.9), time to implanted valve degeneration (13 +/- 5 vs 11 +/- 2 years, p = 0.3), and size of bioprosthesis (30 +/- 2 vs 31 +/- 2 mm, p = 0.14) of the implanted Hancock and C-E valves were similar. Anterior leaflet was flail in 15 versus flail posterior leaflet in 5 patients (p = 0.0004). Eccentric posterior mitral regurgitation jet was present in 12, eccentric anterior jet in 2, central jet in 2, and paravalvular jet in 3 patients. Stenosis of bioprosthesis was present in 1 1 Hancock versus 1 C-E valve (p = 0.06). Stent creep at any stent post was present in 14 Hancock versus no C-E valve (p = 0.0013). Large commissural dehiscence was present in 5 C-E versus 1 Hancock valve (p = 0.0006). Ring margin perforation was the most common perforation in Hancock valves (p <0.05, analysis of variance versus all other Hancock perforations). Dehiscence at the stent posts was the most common perforation in C-E valves (p <0.05 vs other C-E perforations, analysis of variance and p <0.001 versus Hancock valves). Thus, Hancock valves showed greater stenosis and stent creep, whereas C-E valves showed large dehiscences at the stent posts on explantation. The anterior leaflet degenerated most frequently in both valves. These findings suggest that the valve design may influence the mechanisms of porcine valve degeneration.

Bloody pericardial effusion in patients with cardiac tamponade: is the cause cancerous, tuberculous, or iatrogenic in the 1990s?

STUDY OBJECTIVES

The decrease in incidence of tuberculosis, along with the increase in invasive cardiovascular procedures, may have changed the frequency of causes of bloody pericardial effusion associated with cardiac tamponade, although this is not yet recognized by medical textbooks. We analyzed the causes of bloody pericardial effusion in the clinical setting of cardiac tamponade in the 1990s; patients' survival; the effect of laboratory results on discharge diagnosis; and how often bloody pericardial effusion is a presenting manifestation of a new malignancy or tuberculosis.

DESIGN

Retrospective, observational, single-center study.

SETTING

A community hospital.

PATIENTS

The charts of all patients who underwent pericardiocentesis for cardiac tamponade and had bloody pericardial effusion were retrospectively reviewed.

RESULTS

Of 150 patients who had pericardiocentesis for relieving cardiac tamponade, 96 patients (64%) had a bloody pericardial effusion. The most common cause of bloody pericardial effusion was iatrogenic disease (31%), namely, secondary to invasive cardiac procedures. The other common causes were malignancy (26%), complications of atherosclerotic heart disease (11%), and idiopathic disease (10%). Tuberculosis was detected as a cause of bloody pericardial effusion in one patient and presumed to be the cause in another patient. Bloody pericardial effusion was found to be a presenting manifestation of a newly diagnosed malignancy in two patients. The patients in the idiopathic and iatrogenic groups were all alive and had no recurrence of pericardial effusion at 24 +/- 27 and 33 +/- 21 months after hospital discharge, respectively, whereas 80% of patients with malignancy-related bloody effusions died within 8 +/- 6 months.

CONCLUSIONS

In a patient population that is reasonably representative of that in most community hospitals in the United States, the most common cause of bloody pericardial effusion in patients with signs or symptoms of cardiac tamponade is now iatrogenic disease. Of the noniatrogenic causes, malignancy, complications of acute myocardial infarction, and idiopathic disease predominated. Hemorrhagic tuberculous pericardial effusions are uncommon and may likely reflect a low incidence of cardiac tuberculosis in community hospitals in the United States.

Myocardial contractile reserve on dobutamine echocardiography predicts late spontaneous improvement in cardiac function in patients with recent onset idiopathic dilated cardiomyopathy

OBJECTIVES

The purpose of this study was to determine whether identification of contractile reserve with dobutamine would predict recovery of myocardial function during follow-up in patients with recent onset idiopathic dilated cardiomyopathy (IDC).

BACKGROUND

The prognosis of patients presenting with new onset IDC is variable and difficult to predict.

METHODS

Twenty-two patients (17 men, 5 women, 46 +/- 14 years) with recently diagnosed IDC (4 +/- 3 months) underwent dobutamine echocardiography. Left ventricular ejection fraction (LVEF) and LV sphericity before and at peak dobutamine infusion (30 +/- 11 microg/kg/min) were determined. A follow-up echocardiographic assessment was done at 6 +/- 4 months.

RESULTS

The LVEF on dobutamine was directly related to baseline LV mass expressed as g/ml (Pearson r = 0.65, p = 0.0003). Baseline variables that were significantly predictive of follow-up LVEF were deceleration time (r = 0.69, p = 0.0006), wall motion score index (WMSI) (r = -0.63, p = 0.002), LV mass (r = 0.56, p = 0.008) and LVEF on dobutamine (r = 0.84, p = 0.0001). When either deceleration time or WMSI or LV mass was entered into a regression equation to predict follow-up LVEF, the LVEF on dobutamine added significantly to predictive power. However, if LVEF on dobutamine was entered first, none of the other three variables added significantly to prediction. Baseline LV sphericity at end diastole (ED) (r = 0.13, p = 0.6) did not correlate with follow-up LV sphericity in ED, whereas LV sphericity in ED on dobutamine (ED [r = 0.70, p = 0.0004]) correlated with LV sphericity in ED on follow up.

CONCLUSIONS

This study demonstrates that dobutamine-induced improvement in baseline LVEF and LV sphericity identifies patients with IDC who exhibit substantial improvement in LV function and geometry over time.

Syphilitic lymphadenopathy. Histology and human immunodeficiency virus status

Few reports on syphilitic lymphadenopathy have appeared in 20 years, and none have compared findings in patients with and without human immunodeficiency virus (HIV) infection, despite the recent epidemic spread of syphilis and HIV. Twelve cases of syphilitic lymphadenopathy were studied and grouped according to HIV status. Patients were 21 to 62 years old (median, 29 years); 7 were men, 5 were women. Biopsy sites were cervical (7 cases), inguinal (4), and axillary (1) lymph nodes. All patients had evidence of syphilis. Rapid plasma reagin titers ranged from 1:32 to 1:512. Treponemal hemagglutination was positive in all cases tested. Spirochetes were found with Steiner staining in 2 cases. HIV testing was positive in 4, negative in 2, and unknown in 6 cases. Lymph nodes were enlarged and often fragmented due to capsular fibrosis and chronic inflammation, with focal obliteration of the subcapsular sinus. Follicular and interfollicular hyperplasia was seen in all cases and was usually marked, with prominent vascular proliferation, plasma cells, immuno-blasts, histiocytes, and occasional neutrophils. Follicle lysis and granulomas suggestive of unconfirmed toxoplasmosis were each seen in 1 case, and Kaposi sarcoma in 2, all in HIV-positive patients. Lymphoplasmacytic infiltration was marked, especially in interfollicular areas, with peri-vascular plasma cell cuffing in all cases and obliterative endarteritis in about half (7 of 12, 56%). Immunostaining for CD45RO (UCHL-1), CD20 (L26), kappa, lambda, and CD68 (Kp-1) revealed a mixed population of T cells, polyclonal B cells, and interfollicular histiocytes. Distribution of T and B cells (immunoarchitecture) was essentially normal and similar in all cases, regardless of HIV status. Syphilis produces essentially identical findings in lymph nodes in both HIV-positive and HIV-negative patients. The morphologic findings described should prompt evaluation for infection with Treponema pallidum and, in light of the current epidemic, HIV.

Transesophageal echocardiographic identification of an abdominal aortic pseudoaneurysm complemented by a transpulmonary echo contrast agent

Pseudoaneurysm of the abdominal aorta, a rare complication after traumatic injuries, represents a diagnostic challenge for which sophisticated imaging modalities are often used for its early identification. We describe a case in which transesophageal echocardiographic examination complemented by a transpulmonary echo contrast agent was useful not only in demonstrating the pseudoaneurysm, but in helping to localize the intravascular communication between the aorta and the pseudoaneurysm.

Clinical validation of intravascular ultrasound imaging for assessment of coronary stenosis severity: comparison with stress myocardial perfusion imaging

OBJECTIVES

To validate intravascular ultrasound (IVUS) measurements for differentiating functionally significant from nonsignificant coronary stenosis.

BACKGROUND

To date, there are no validated criteria for the definition of a flow-limiting coronary artery stenosis by IVUS.

METHODS

Preinterventional IVUS imaging (30-MHz imaging catheter) of 70 de novo coronary lesions was performed. The lesion lumen area and three IVUS-derived stenosis indixes comparing lesion lumen area with the lesion external elastic lamina (EEL) area, the mean reference lumen area and the mean reference EEL area were compared with the results of stress myocardial perfusion imaging.

RESULTS

The lesion lumen area and three IVUS-derived stenosis indexes showed sensitivities and specificities ranging between 80% and 90% using stress myocardial perfusion imaging as the gold standard. The lesion lumen area < or =4 mm2 is a simple and highly accurate criterion for significant coronary narrowing.

CONCLUSIONS

Quantitative IVUS indices can be reliably used for identifying significant epicardial coronary artery stenoses.

Ultrasonic thrombolysis: catheter-delivered and transcutaneous applications

Ultrasonic thrombolysis has been proved to be an efficient and safe modality for the treatment of acute arterial occlusions in vitro and in vivo in animal studies. There have been and are ongoing parallel improvements in ultrasound technology and adjuvant pharmacological treatments for therapeutic applications. Thus therapeutic ultrasound for thrombolysis holds great promise in overcoming the limitations of current available therapies.