Predictors and outcomes of acute, sub-acute and early stroke following transcatheter aortic valve implantation

Background

Stroke is one of the most devastating complications after transcatheter aortic valve implantation (TAVI). The recent third Valve Academic Research Consortium (VARC-3) proposes new stroke terminology according to time between TAVI and stroke onset.

Purpose

We aimed to identify predictors and assessed mortality in patients undergoing transfemoral TAVI complicated by acute, sub-acute and early stroke.

Methods

Patients undergoing transfemoral TAVI were included in a global patient level database. Acute stroke was defined as stroke occurring ≤24 hours after the index procedure. Sub-acute stroke was defined as stroke occurring between >1 day and ≤30 days and early stroke as >30 and ≤365 days following TAVI, according to VARC-3. We identified predictors for these complications using multivariate logistic regression analysis and assessed mortality outcomes in these patients.

Results

A total of 11230 patients underwent transfemoral TAVI. Mean age was 81.5±7.0 years, 58% was female and median STS-PROM score was 6.5% (4.0%-13.2%). A total of 405 (3.6%) experienced stroke during the first year after TAVI. Of these 93 (23%) had acute stroke, 195 (46%) sub-acute stroke and 117 (27%) early stroke. One year mortality was highest after acute stroke (56.9%), followed by sub-acute stroke (41.7%), and early stroke (29.0%), but one-year mortality in all stroke patients was higher than in non-stroke patients (40.5% vs 15.8%, p<0.001). Glomerular filtration rate was an independent predictor for acute stroke (odds ratio [OR] 0.9, 95% confidence interval [CI] 0.9–1.0, p=0.03). Previous cerebrovascular events independently predicted sub-acute stroke (OR 2.1, 95% CI 1.4–3.1, p=0.001). Independent predictors for early stroke were age (OR 1.0 per year, 95% CI 1.0–1.0, p=0.04) and peripheral vascular disease (OR 2.0, 95% CI 1.4–3.0, p<0.001).

Conclusions

Patients undergoing transfemoral TAVI complicated by stroke showed higher one-year mortality than non-stroke patients. Earlier timing of post-TAVI stroke was associated with increased mortality. Acute stroke was predicted by renal impairment; sub-acute stroke by previous cerebrovascular events and early stroke by age and peripheral vascular disease, suggesting different pathways leading to stroke in these patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Hartstichting

C28 THE FINANCIAL BURDEN OF NEWER GENERATION TAVI DEVICES: RESULTS FROM THE ITALIAN OBSERVANT STUDIES

Objectives

To estimate the financial burden of using newer generation transcatheter aortic valve implantation (TAVI) devices compared with older generation devices.

Background

TAVI is becoming the standard treatment for severe aortic stenosis in symptomatic elderly patients and is increasingly offered also to younger and lower risk patients. Resource utilization in performing TAVI has become an important focus due to the high likelihood of hospital readmissions, but it is unclear whether readmissions after TAVI contribute to a significant proportion of overall costs of TAVI to the healthcare system at mid–term follow up.

Methods

A probabilistic Markov model was developed in order to estimate the cost consequence of introducing newer generation TAVI devices were calculated as the absolute deterministic difference between a cohort of 6,000 patients treated with the newer TAVI devices (TAVI–new scenario) and the same cohort treated with old TAVI devices (TAVI–old scenario). Transition probability and hospitalization costs were retrieved among patients enrolled in the OBSERVANT I and OBSERVANT II studies; 1898 patients treated with older generation TAVI devices and 1417 patients treated with new generation TAVI devices were compared. Outcomes were adjusted using propensity score matching.

Results

Propensity score matching resulted in 853 pairs, whose baseline risk factors were well balanced. The mean EuroSCORE II (6.6 vs. 6.8; p = 0.76) and the mean age (82.0 vs 82.1; p = 0.62) of older generation TAVI patients and newer generation TAVI patients were similar. The use of newer generation TAVI devices determined a significant reduction of re–hospitalizations (–30.5% re–intervention, –25.2% major re–hospitalization and –30.8% minor re–hospitalization) and mortality (–20%). These reductions were associated with significant cost savings over a 1–year period (−€4.1 million in terms of direct costs and −€19.7 million considering the additional cost of the devices). The main cost–reduction was estimated for re–hospitalization that cover 79% of the overall cost reduction in the economic analysis without the costs of the devices.

Conclusions

After adjusting for baseline characteristics, patients undergoing TAVI with newer generation devices had lower risk of all–cause death and re–hospitalization. These reductions are leading to significant cost savings at 1 year, mainly due to the reduction in re–hospitalization costs.

Clinical impact and evolution of mitral regurgitation after TAVI using the new generation self-expandable valves

BACKGROUND

Concomitant mitral regurgitation (MR) impaired prognosis in patients undergoing transcatheter aortic valve implantation (TAVI). It has been suggested that the use of first generation self-expandable valve in patients with significant MR is associated with worse outcome as compared with balloon expandable valve. However, the impact of newer generation transcatheter devices on MR has not been investigated so far. We aim to assess the prognostic impact of MR in patients undergoing TAVI with the first-generation vs. the latest generation of self-expandable valves.

METHODS

We analyzed 2964 consecutive patients who underwent TAVI. Patients were classified into 4 groups according to the degree of baseline MR and the generation of self expandable valve implanted.

RESULTS

Of 1234 patients with moderate or severe MR, 817 were treated with first generation and 417 patients with second generation valves. Whereas, of 1730 patients with no or mild MR, 1130 were treated with first generation and 600 patients with second generation valves. Although, concomitant moderate-severe MR was found to be an independent predictor of mortality after TAVI, the use of newer generation self expandable valves was associated with higher survival rate at 1 year irrespective of the degree of preprocedural MR. At multivariable analysis the use of newer generation valve was associated with MR improvement throughout 1 year follow-up.

CONCLUSION

Baseline moderate-severe MR is associated with an increase in mortality after TAVI. However, the degree of preprocedural MR doesn't impact survival when a second generation self expandable valve is used.

Obesity paradox in 12,381 patients undergoing transfemoral transcatheter aortic valve implantation: from the CENTER-collaboration

Background

Transcatheter aortic valve implantation (TAVI) is a well-established treatment for symptomatic aortic valve stenosis. The majority of patients treated are overweight or obese. Obesity has traditionally been linked to reduced survival and worse cardiovascular outcomes. However, an “obesity paradox” has been described in some diseases, with improved survival of obese patients after invasive and surgical procedures.

Methods

The CENTER-collaboration included data from 10 registries or clinical trials of patients undergoing transfemoral TAVI from 2007 to 2018. Patients were divided in four groups according to body mass index (BMI): underweight: BMI <18.5 kg/m2, normal weight: BMI 18.5 to 24.9 kg/m2, overweight: BMI 25 to 29.9 kg/m2, and obese: BMI ≥30 kg/m2. The primary endpoints of this analysis were differences in 30-day all-cause mortality and stroke after TAVI.

Results

Of the 12,381 patients analysed, 2% (n=205) were underweight, 29% (n=3552) had normal weight, 44% (n=5460) were overweight and 25% (n=3140) obese. Older patients had lower BMI (median of 84 years for underweight and 81 years for obese patients, p<0.001). Cardiovascular risk factors such as hypertension, diabetes mellitus and dyslipidaemia increased progressively with increase of BMI category. As to clinical outcomes, there were no differences for stroke rates across BMI groups. In-hospital mortality was highest in patients who were underweight, namely 8.4%, compared to normal weight, overweight and obese patients (6.2%, 4.3% and 4.6% respectively, p<0.001) as was 30-day mortality (9.8% compared to 6.9%, 5.3% and 5.2% respectively, p=0.001). On the other hand, extremely obese patients (BMI ≥40.0 kg/m2) also had worse prognosis, with a 30-day mortality of 7.6%.

Conclusions

In this global analysis of more than 12 000 patients undergoing transfemoral TAVI, overweight and obese patients had better in-hospital and 30-day survival than normal weight patients, confirming the obesity paradox. There was an inverted J-shaped relationship of body mass index with prognosis, with higher mortality rates for underweight and extremely obese patients.

Mortality and stroke per BMI category

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Dutch Heart Foundation; Netherlands Organisation for Health Research and Development

Predictors of haemodynamic performance in patients with aortic stenosis and small annulus undergoing TAVI with self-expandable valves

Background

Small aortic annular size is one of the most important predictor of poor hemodynamic and clinical outcomes in patients treated for aortic stenosis. Post-hoc analyses of pivotal trials showed that transcatheter aortic valve intervention (TAVI) offer better outcomes then surgery in patients with small aortic annulus, especially with self-expandable valves (SEV). However, data about SEVs comparison in this population are limited.

Purpose

Our aim is to assess how valve design and oversizing, with anatomical and echographic features, impact on the hemodynamic performance of SEVs in TAVI patients with small aortic annulus.

Methods

The TAVI SMALL registry enrolled 859 patients with small aortic annulus (CT-scan annular perimeter≤72 mm or area ≤400 mm2) treated for aortic stenosis with currently available SEVs (Evolut R=397; Evolut PRO =84; Acurate Neo=140; Acurate TA= 61; Portico=177) at 9 European centers between 2011 and 2018. We performed multivariable backward logistic regression analyses to identify predictors of high postprocedural mean gradient, moderate-to-severe PPM, and moderate-to-severe para-valvular leak (PVL).

Results

After adjustment for LVEF, we identified annular perimeter and percentage of oversizing as independent predictors of lower post-procedural mean gradient.

Implantation of intra-annular rather than supra-annular bioprosthesis was the only independent predictor of moderate-to-severe PPM.

Predictors of moderate-to-severe PVL are reported in the Table.

Conclusions

Among patients with aortic stenosis and small aortic annulus treated with transcatheter SEVs, use of supra-annular bioproshtesis and oversizing were associated with improved valve performance.

Funding Acknowledgement

Type of funding source: None

Therapeutic Effect of a Low Molecular Weight Dermatan Sulphate (Desmin 370) in Rat Venous Thrombosis - Evidence for an Anticoagulant-Independent Mechanism

We evaluated the capacity of a low molecular weight dermatan sulphate (D370) to prevent thrombus formation and to induce a reduction of a stabilized thrombus in a rat venous thrombosis model. Injection of D370, 10 min before induction of venous stasis (prevention model), prevented thrombus formation in a dose-dependent way (ED50: 2.3 mg/kg). When given to rats 6 h after induction of venous stasis (therapeutic model), D370 caused a time- and dose-dependent reduction in thrombus size (60% to 70% reduction 2 h after injection of 10 mg/kg). At comparable antithrombotic dosages (i.e. minimum dose giving complete inhibition of thrombus formation), heparin (0.5 mg/kg) only caused 40% reduction of a preformed thrombus while hirudin (1 mg/kg) was virtually ineffective (less than 10% reduction in weight). All three compounds inhibited 125I-fibrin(ogen) deposition on 6-h aged thrombi by more than 85%, suggesting that D370 and, to a lesser extent, heparin reduce thrombus size via mechanisms other than inhibition of thrombus accretion. The involvement of a fibrinolysis-mediated mechanism in the D370-induced effect is suggested by the following. EACA (1 g/kg), when given to thrombus-bearing control animals, did not influence thrombus weight. However, when administered before D370 treatment, it prevented the expected reduction in thrombus weight by more than 80%, without influencing the effect of D370 on 125I-fibrin(ogen) accumulation onto preexisting thrombi. D370 injection caused neither an enhancement of fibrinolytic activity nor a reduction of PAI in plasma. In vitro, D370 (200 μg/ml) was unable to potentiate the spontaneous or PA-induced lysis of 125I-fibrinogen labelled blood, plasma, or purified fibrin clots. It is suggested that prevention of thrombus formation by D370 is related mainly to inhibition of blood coagulation, whereas reduction of the weight of aged thrombi is primarily due to an anticoagulant-independent mechanism, most probably involving local enhancement of the fibrinolytic process. D370 may represent an alternative pharmacologic agent both in the prevention and in the therapy of venous thrombosis.

Transcatheter Aortic Valve Implantation Experience with SAPIEN 3

Based on randomized trials with first generation devices, transcatheter aortic valve replacement (TAVI) has been included into the treatment strategy for high-risk and inoperable patients with severe aortic stenosis. Procedural complications remain a concern with TAVI, including stroke, vascular complications, paravalvular leak (PVL) and conduction disturbances. Addressing these limitations will support TAVI use in lower risk populations. This review discussed features and most recent clinical evidence of the new balloon-expandable THV (SAPIEN 3, Edwards Lifescience, Irvine, CA, USA).

Update on percutaneous mitral valve therapy: clinical results and real life experience

Mitral regurgitation (MR) is a common valvulopathy worldwide increasing in prevalence. Cardiac surgical intervention, preferable repair, is the standard of care, but a relevant number of patients with severe MR do not undergo surgery because of high peri-operative risk. Percutaneous mitral valve repair with the MitraClip System has evolved as a new tool for the treatment of severe MR. The procedure simulates the surgical edge-to-edge technique, developed by Alfieri in 1991, creating a double orifice valve by a permanent approximation of the two mitral valve leaflets. Several preclinical studies, registries and Food and Drug Administration approved clinical trials (EVEREST, ACCESS-EU) are currently available. The percutaneous approach has been recently studied in a randomized controlled trial, concluding that the device is less effective at reducing MR, when compared with surgery, by associated with a lower adverse event rate. The patients enrolled in this trial had a normal surgical risk and mainly degenerative MR with preserved left ventricular function. On the other hand, results derived from the clinical "real life" experience, show that patients actually treated in Europe present a higher surgical risk profile, more complex mitral valve anatomy and functional MR in the most of cases. Thus these data suggest that MitraClip procedure is feasible and safe in this subgroup of patients that should be excluded from the EVEREST trial due to rigid exclusion criteria. Despite the promising results clinical experience is still small, and no data related the durability are currently available. Therefore, MitraClip device should be reserved now to high risk or inoperable patients.

Reduction of mitral valve regurgitation with Mitraclip® percutaneous system

Mitral regurgitation (MR) is the second most common heart valve disease worldwide and the current gold-standard treatment is surgical repair or replacement. Nevertheless, many patients do not undergo surgical intervention due to several comorbidities. Percutaneous "edge-to-edge" mitral valve repair using the MitraClip System is an emerging and effective option to this subset of patients. This device has been used to treat both functional and degenerative mitral valve regurgitation and has been compared to surgery in the Endovascular Valve Edge-to-Edge Repair Study II (EVEREST II) randomized trial. Although the field of percutaneous management of MR is at an early stage, it has been demonstrated that percutaneous approaches can reduce MR, suggesting there is a great deal of potential for clinical benefit to patients with MR.

Antithymocyte globulin for graft-versus-host disease prophylaxis in transplants from unrelated donors: 2 randomized studies from Gruppo Italiano Trapianti Midollo Osseo (GITMO)

One hundred nine patients with hematologic malignancies, undergoing bone marrow transplants (BMT) from unrelated donors, were randomized in 2 consecutive trials to receive or not to receive antithymocyte globulin (ATG) in the conditioning regimen, as follows: (A) 54 patients (median age, 28 years; 39% with advanced disease) were randomized to no ATG (n = 25) versus 7.5 mg/kg rabbit ATG (Thymoglobulin; Sangstat, Lyon, France) (n = 29); (B) 55 patients (median age, 31 years, 71% with advanced disease) were randomized to no ATG (n = 28) versus 15 mg/kg rabbit ATG (n = 27). Grade III-IV graft-versus-host disease (GVHD) was diagnosed in 36% versus 41% (P =.8) in the first and in 50% versus 11% (P =.001) in the second trial. Transplant-related mortality (TRM), relapse, and actuarial 3-year survival rates were comparable in both trials. In fact, despite the reduction of GVHD in the second trial, a higher risk for lethal infections (30% vs 7%; P =.02) was seen in the arm given 15 mg/kg ATG. Extensive chronic GVHD developed overall more frequently in patients given no ATG (62% vs 39%; P =.04), as confirmed by multivariate analysis (P =.03). Time to 50 x 10(9)/L platelets was comparable in the first trial (21 vs 24 days; P =.3) and delayed in the ATG arm in the second trial (23 vs 38 days; P =.02). These trials suggest that (1) 15 mg/kg ATG before BMT significantly reduces the risk for grade III-IV acute GVHD, (2) this does not translate to a reduction in TRM because of the increased risk for infections, and (3) though survival is unchanged, extensive chronic GVHD is significantly reduced in patients receiving ATG.

Bone marrow transplantation from unrelated donors: the impact of mismatches with substitutions at position 116 of the human leukocyte antigen class I heavy chain

The hypothesis was tested that amino acid substitutions in specific positions within human leukocyte antigen class I heavy chain would have different impacts on transplant-related mortality (TRM) in patients receiving transplanted bone marrow from unrelated donors. One hundred patients and their unrelated donors were typed by sequence-based typing for the human leukocyte antigen (HLA)-A, -B, and -C loci. All pairs were matched for DRB1, DRB3, DRB4, DRB5, DQA1, and DQB1 loci. Forty pairs were also matched at class I, and 60 pairs had one or more mismatches at class I loci. It was found that substitutions at positions 116 and 114 of class I heavy chain significantly increased the risk for TRM in univariate and bivariate Cox analyses. Conversely, no association between number of multiple mismatches or number of amino acid substitutions and TRM was seen when positions 116 and 114 were adjusted for. Variables predictive of TRM in multivariate Cox analysis were number of cells infused, diagnosis (chronic myeloid leukemia [CML] or non-CML), and amino acid substitution at position 116 or 152. The only variable predictive of severe acute graft-versus-host disease (GVHD) in multivariate Cox analysis was substitution at position 116. Actuarial risk for acute GVHD grade III-IV, TRM, and relapse in pairs with substitutions at position 116 (n = 37) compared to other pairs (n = 63) was, respectively, 36% versus 14% (P =.01), 59% versus 28% (P =.001), and 25% versus 31% (P =.4). In conclusion these data suggest that substitutions at position 116 of class I heavy chain increase the risk for acute GVHD and TRM in patients who receive transplanted bone marrow from unrelated donors.

Alternative donor transplants for patients with advanced hematologic malignancies, conditioned with thiotepa, cyclophosphamide and antithymocyte globulin

Preparative regimens without total body irradiation (TBI) have been reported for alternative donor hemopoietic stem cell transplants (HSCT). Between 7 September 1994 and 7 June 1999 48 patients with advanced hematologic malignancies were conditioned with thiotepa (THIO) 15 mg/kg, cyclophosphamide (CY) 150 mg/kg and antithymocyte globulin (ATG). Donors were HLA mismatched family members (1-2 antigens) (FAM) (n = 24, median age 31 years) or HLA matched unrelated donors (UD) (n = 24, median age 34 years). GVHD prophylaxis was cyclosporine and methotrexate. Stem cell source was peripheral blood (n = 8) or bone marrow (n = 40). Hematologic recovery was seen in 42/46 (91%) evaluable patients and complete chimerism in 31/37 patients (85%). Acute GVHD grades III-IV were seen in 10/46 patients surviving 10 days (21%) and extensive chronic GVHD in 2/36 patients surviving 100 days (5%). Twenty-six patients died (54%), eight of recurrent disease (17%) and 18 of transplant-related complications (37%): main causes of TRM were GVHD (15%), infections (15%) and graft failure (4%). Twenty-two patients (46%) survive with a median follow-up of 877 days (287-1840). The actuarial 3-year survival is 49% for FAM and 42% for UD transplants. Results obtained with this regimen in unrelated grafts for advanced CML (n = 15) were not significantly different when compared to 21 concurrent UD grafts for advanced CML prepared with CY-TBI. In conclusion, the combination of THIO-CY-ATG allows engraftment of alternative donor hemopoietic stem cells. Results are similar when using unrelated matched donors or partially mismatched family donors, and not significantly different when compared to patients conditioned with CY-TBI.

Analysis of the turin umbilical cord blood bank registry

BACKGROUND

The polymorphic nature of the HLA system reduces a patient's probability of finding an HLA-compatible unrelated bone marrow (BM) donor, even though more than 6 million individuals are enrolled in international registries. Recently, umbilical cord blood (UCB) has been successfully employed as a source of HPCs. The use of such cells reduces the risk of GVHD and allows transplants with one or two HLA mismatches. UCB represents an expensive resource: therefore, it is necessary to carefully manage the UCB unit inventory.

STUDY DESIGN AND METHODS

The current study analyzed the genetic heterogeneity of HLA-A, -B, and -DR gene frequencies between pools of UCB and unrelated-donor BM in the Piedmont (an administrative region of Italy). An Italian hematology patient's probability of finding complete or partial matches as a function of donor pool size was determined by considering subsamples randomly selected from the local unrelated BM donors.

RESULTS

The HLA gene frequencies in UCB and unrelated-donor BM pools were not significantly different. The search simulation, based on actual HLA phenotypes, showed that the percentage of Italian patients matched with an HPC unit increases remarkably if 1 or 2 mismatches are accepted, reaching a proportion of 90 percent with an inventory of only about 500 units, while the increment is not so remarkable if the number of UCB units is greater.

CONCLUSION

To optimize economic resources and to be internationally competitive, UCB banks should aim to increase the genetic heterogeneity of their units rather than increasing the UCB inventory, acquire efficient quality control systems, and acquire and preserve UCB units with a greater number of nucleated cells.

[Genetic analysis of Italian hematologic patients candidates for bone marrow transplantation from unrelated donors]

Frequencies of HLA-A, -B and -DR antigens and haplotypes were determined in 1945 Italian patients suffering from hematologic diseases and requiring bone marrow transplantation from unrelated donors. These frequencies were compared with those obtained from the Italian bone marrow donor population. No significant differences were found when considering the number of comparisons made, suggesting that the genetic structure of the Italian patients is not different from that of the Italian donor population.

[The Italian Registry of Bone Marrow Donors: genetic structure and recruitment strategy]

The genetic structure of the Italian bone marrow donor population was analysed by estimating the HLA-A, -B and -DR gene and haplotype frequencies for the total population and for the Italian administrative regions. The haplotype frequencies were used to predict the probability of finding HLA-compatible donors for Italian patients depending on the registry size, and the probability of recruiting in the different Italian regions a donor with a new phenotype. The analysis of these probabilities allows us to propose strategies for donors recruitment in order to increase the phenotypic variability of the registry, then its efficiency.

[The Italian Registry of Bone Marrow Donors]

Following a synthetic statement of the scientific, genetic and practical assumptions of the bone marrow transplantation (BMT) from marrow unrelated donor (MUD), which, in turn, have represented the basis for the establishment of the Italian Bone Marrow Donor Registry (IBMDR), the paper reports the registry activity on 30 November 1998. At that date, Italian volunteers were 232,876, number which put the IBMDR as the fourth registry all over the world and as the third in Europe. The mean age of the donors is 34 years, and this means that IBMDR is one of the youngest among international registries. Using Italian donors, 426 BMT, altogether, have been performed, (248 for Italian patients and 178 for foreign patients). Donor search activations performed by national and international transplant centres have been, at the same date, 5729 (1821 for Italian patients and 3908 for foreign patients). Operating standards and guidelines for all centres participating in the IBMDR are reported in this issue.

Peripheral blood stem cell collection from G-CSF-stimulated unrelated donors for second transplant

Peripheral blood stem cells (PBSCs) collected following stimulation with cytokines are commonly used for autologous haematopoietic transplants. Currently, PBSCs are being used for syngeneic or allogeneic transplants from matched or haploidentical donors. However, many issues are still unanswered regarding the early or late side-effects cytokines have on recipients and on healthy donors. The aims of this paper were to evaluate the experience acquired worldwide in this field, to define the acceptability of stem cell donation by G-CSF-stimulated apheresis from unrelated donors after the failure of a first donation, and to assess side-effects of G-CSF on unrelated donors. The use of PBSCs has increased tremendously over the last few years and in the near future PBSCs will probably become the most relevant source of stem cells. Studies conducted so far have definitely concluded that G-CSF is safe and well tolerated. Results observed in transplants utilizing marrow stem cells compared with results obtained in transplants utilizing PBSCs have shown that patients undergoing this latter procedure recover earlier, require a lower number of transfusions and spend fewer days in hospital with a consequent decrease in costs. We concluded that a second transplant by G-CSF-stimulated apheresis from an unrelated donor is definitely acceptable and we designed a prospective study to better define all controversial aspects. Donors will be given 10 microg/kg/day of G-CSF subcutaneously for 5 days. One or two PBSC collection procedures will be performed: the first on day 5 and the second, if necessary, on day 6. Donors will be surveyed and blood counts monitored in a standardized manner during the process.

HLA polymorphisms in Italian bone marrow donors: a regional analysis

The aim of this study was to analyse the genetic structure of the Italian bone marrow donor population on the basis of HLA polymorphisms. Maximum likelihood estimates of gene and haplotype frequencies, goodness of fit to Hardy-Weinberg predictions and heterozygosity were calculated for 18 Italian administrative regions. Moreover, the phenotypic peculiarity of the regional populations was assessed by analysing the number of "typical phenotypes" found in each region. Multivariate analyses carried out on HLA-A and HLA-B gene frequencies gave a genetic pattern of the donor pools that reflects the structure of the Italian population determined in previous population genetic studies. Sardinia shows a very large genetic difference with respect to the other regions; of these, the central-southern regions are well-differentiated from the central-northern. Southern regions present higher genetic heterogeneity and a higher probability of providing donors with phenotypes not already present in the Italian bone marrow registry. The large sample size of the bone marrow donor registry allowed us to estimate gene and haplotype frequencies with greater accuracy than in previous studies. Our results may be of use in determining strategies for donor recruitment and selecting unrelated donors for patients requiring bone marrow grafting, as well as for anthropological, epidemiological and population genetics studies.

Prevention and therapy of experimental venous thrombosis in rabbits by desmin 370

Desmin 370 (D370), a low molecular weight dermatan sulfate, has been shown to reduce the size of preformed thrombi in rats, via a mechanism largely independent of its anticoagulant activity. In the present study we investigated the therapeutic efficacy of D370 in rabbits with experimental jugular vein thrombosis. Experiments performed to evaluate the antithrombotic dosages in rabbits indicated that D370 prevented the formation of venous thrombi (Wessler model) in a dose-dependent manner with complete inhibition at 20 mg/kg. When injected to rabbits bearing a 30 min aged thrombus, D370 caused a time- and dose-dependent reduction in thrombus weight. Thrombi harvested 2 h after injection of 50 mg/kg of D370 were 71% smaller than thrombi from saline-treated rabbits and 50% smaller than pretreatment thrombi, suggesting a double effect of the drug: inhibition of thrombus accretion and reduction of the existing thrombus. Interestingly, pretreatment with the fibrinolytic inhibitor EACA (1 g/kg), significantly attenuated the therapeutic efficacy of D370, suggesting a possible involvement of the fibrinolytic system. Heparin (50 and 200 U/kg) was less active as therapeutic agent, the maximal decrease in thrombus weight, as compared to untreated rabbits, amounting to 38%. Heparin, moreover, caused a more pronounced prolongation of APTT than comparable antithrombotic dosages of D370. Our present data extend previous results on the therapeutic efficacy of D370 and underscore its potential as an alternative antithrombotic drug.

Unrelated donor marrow transplantation for chronic myelogenous leukaemia

Between January 1989 and July 1995 the search for an unrelated donor (UD) was started for 379 consecutive Italian patients with Philadelphia positive (Ph+) chronic myelogenous leukaemia (CML). 89 (23%) were transplanted. The overall probability of transplant before and after December 1991 was 16% and 49%, respectively (P=0.0001), and average interval between search activation and graft was 23 months and 13 months, respectively (P=0.0001). Disease-free survival (DFS) following 60 consecutive transplants performed before February 1996 was 41.5% at 48 months and was 64% for patients grafted after January 1993. In univariate analysis, five variables had a favourable effect on DFS: year of bone marrow transplantation (BMT) after 1993 (P=0.0002), HLA-DRB1 donor/recipient (D/R) match (P=0.0006), total body irradiation (TBI) containing regimen (P=0.0006), graft-versus-host disease (GvHD) prophylaxis including 'early' cyclosporin before the transplant, and a marrow cell dose > 3 x 10(8)/kg of recipient body weight (P=0.04). Multivariate analysis confirmed that HLA identity (P=0.006), TBI-containing regimen (P=0.0001) and 'early cyclosporin' (P=0.04) were associated with higher DFS. Transplant-related mortality (TRM) was 67% in patients grafted before January 1993 and 30% in patients grafted subsequently (P=0.002). Multivariate analysis confirmed DRB1 identity (P=0.03) and TBI-containing regimen (P=0.0005) to be independent factors predictive of low TRM. This suggests that the outcome of patients transplanted from an HLA DRB1 matched donor, after a TBI-containing preparative regimen, is similar to results recently reported in patients transplanted from geno-identical siblings. These results indicate that the search should be initiated at diagnosis for patients < 45 years of age and UD BMT should be considered early in the disease course for those with an available DRB1-matched unrelated donor.

Bone marrow transplantation for chronic myeloid leukemia (CML) from unrelated and sibling donors: single center experience

This is a report on 60 consecutive patients with chronic myeloid leukemia (CML) who received an allogeneic bone marrow transplant (BMT) in this Unit. Donors were HLA-identical siblings (SIB) (n = 36) or unrelated donors (MUD) (n = 24) matched by serology for HLA A and B and by molecular biology for HLA DR. All patients were prepared with cyclophosphamide 120 mg/kg and fractionated total body irradiation 10-12 Gy. GVHD prophylaxis consisted of cyclosporin A (CsA) starting on day -7 and short-course methotrexate. Bone marrow was unmanipulated in all cases. Cytomegalovirus prophylaxis consisted of acyclovir for SIBs and foscarnet for MUDs. When compared to SIB transplants, MUD patients were younger (29 vs 36 years; P = 0.002), had younger donors (31 vs 39; P = 0.001), had a longer interval between diagnosis and BMT (1459 vs 263 days; P < 0.001) and received a smaller number of nucleated cells at transplant (3.3 vs 4.4 x 10(8)/kg; P = 0.003). More MUDs had advanced disease (50 vs 17%, P = 0.005). The median day to 0.5 x 10(9)/l neutrophils was similar in both groups (18 days for SIBs vs 17 days for MUDs; P = 0.06); the median platelet count on days +30, +50, +100 was significantly (P < 0.01) higher in SIB than in MUD patients (122 vs 38, 113 vs 50 and 97 vs 45 x 10(9)/l, respectively). Acute GVHD was scored as absent-mild, moderate, or severe, in 36, 58 and 6% of SIBs vs 25, 42 and 33% in MUD patients (P = 0.01). Chronic GVHD was comparable (P = 0.1). The actuarial risk of CMV antigenemia at 1 year was 60% in both groups. There were six deaths in SIB patients (two leukemia, two infections, one GVHD, one pneumonitis) and four deaths in MUD patients (three acute GVHD and one infection). Fifty patients survive with a median follow-up of 656 days for SIBs and 485 for MUDs. The actuarial 3-year transplant-related mortality is 12% in SIBs and 17% in MUDs (P = 0.5); the actuarial relapse is 18% in SIBs vs 6% in MUDs (P = 0.4) and 3-year survival 78% in SIBs vs 82% in MUDs (P = 0.7). This study suggests that survival of CML patients after marrow transplantation from unrelated or sibling donors is currently similar, provided the former are well matched. The increased incidence of GVHD in MUD patients is possibly compensated by a lower risk of relapse.

Bioavailability of Desmin, a low molecular weight dermatan sulfate, after subcutaneous administration to healthy volunteers

The bioavailability of two different s.c. doses of Desmin (a new low molecular weight dermatan sulfate) was evaluated in 12 healthy volunteers (6 men, 6 women aged 22-45 years) who were injected, on 3 separate days and with a wash-out period of at least 21 days between each administration, with 200 and 300 mg of Desmin by the s.c. route and 200 mg by the i.v. route. Immediately before injection and at various times thereafter (after 15 min and 30 min for i.v. only and after 1, 2, 3, 4, 6, 8, 12, and 24 h for both s.c. and i.v. dosing), blood samples were drawn to investigate bioavailability by measuring several coagulation parameters: activated partial thromboplastin time, thrombin time, inhibition of factor Xa, Heptest, and heparin cofactor II. Furthermore the local tolerance of the s.c. and i.v. injections were investigated. The s.c. administration of the two Desmin doses had a negligible effect on the activated partial thromboplastin time and a very small effect on the thrombin time, measured with human thrombin; in contrast, Heptest, heparin cofactor II, and anti-Xa activities increased, with a good drug bioavailability (more than 100%). The plasma effects of Desmin were dose dependent only when measured by Heptest, which also gave a greater response after the s.c. administrations. There were no symptoms of intolerance or pain at the injection site after single i.v. and s.c. Desmin administration.

Thrombolysis enhancing activity of a low molecular weight dermatan sulfate (Desmin 370) in experimental pulmonary embolism in rats

The effect of Desmin 370 (D370), a low molecular weight dermatan sulfate, on the extent of lysis of radiolabelled pulmonary emboli in rats was evaluated. 125I-fibrin labelled blood clots were embolized into the lungs via a jugular vein, and the degree of lysis was calculated, at predetermined intervals, by the residual radioactivity in the lungs. A single i.v. injection of D370 (50 mg/kg) caused a significant increase in the rate of lysis, which was visible at 30 min and persisted for the whole experimental period (2 h). This effect was prevented by epsilon-aminocaproic acid (1 g/kg). At comparable antithrombotic dosages, heparin (2 mg/kg) also produced a significant enhancement of thrombolysis while hirudin (2 mg/kg) was totally ineffective. Heparin, however, produced a much more pronounced anticoagulant effect than D370. No changes in the plasma levels of plasminogen activator and plasminogen activator inhibitor activities were observed after treatment with D370. Moreover, the dermatan sulfate failed to enhance the blood fibrinolytic activity measured by a solid phase 125I-fibrin assay. These results extend previous data indicating that D370 may be efficient also in the therapy of thrombosis and provide direct evidence that this effect occurs, at least in part, via degradation of thrombus associated fibrin.

A new series of 6-chloro-2,3-dihydro-4(1H)-quinazolinone derivatives as antiemetic and gastrointestinal motility enhancing agents

New 6-chloro-2,3-dihydro-4(1H)-quinazolinones (24-27) have been synthesized and evaluated for gastrointestinal prokinetic and antiemetic activities in comparison with structurally related benzamides (21-22) and 6-chloro-2,3-dihydro-(1H)-1,3-benzoxazolin-4-ones (28). Their key pharmacophoric element has been defined as a 6-membered ring replacing the "virtual ring" arising from the hydrogen bond between amidic nitrogen and methoxy group in metoclopramide (1) and structurally related benzamides (2-10). Variations of heterocycle linking groups have pointed out that a lipophilic aromatic group in position 1 plays an important role for pharmacological properties, while the steric restriction and the modification of the side-chain nucleophilicity are uneffective both for the in vitro and in vivo activity. Some of these compounds very effectively enhance gut peristaltic activity in vitro (rabbit jejunum), increase gastric emptying of a semisolid meal (in rats), and inhibit cisplatin-induced emesis (in pigeons), favourably comparing with cisapride.

Unrelated donor marrow transplantation: initial experience of the Italian bone marrow transplant group (GITMO)

From 1 September 1988 to 30 September 1993, a search for an unrelated donor (URD) was started for 633 Italian patients. Eighty-five of them (13%) were transplanted. Despite the introduction of more strict criteria for the selection of compatible donors, the percentage of patients who reached transplant increased significantly after December 1992. For patients who started a search before and after January 1993, respectively the probability of transplant by 8 and 16 months from search activation was 4 and 10%, compared to 22 and 37% (P = 0.0001). The average intervals between search activation and graft were 15 and 8 months respectively, for the first and second group (P = 0.0001). Data of 75 consecutive transplants performed up to March 1994 were analyzed. Actuarial 2-year survival was 15% for patients grafted before 1992 and 40% for those grafted after January 1992. In this latter period, survival of patients with malignant and non-malignant disorders was 32 and 67%, respectively. In univariate analysis, patients younger than 16 years (P = 0.01), patients grafted after 1992 (P = 0.01) and patients receiving the marrow from a 6-antigen matched donor (P = 0.01) showed a higher survival probability. Multivariate analysis did not show any difference, probably due to the low number of patients and to short follow-up. The adoption of stricter and more accurate HLA-matching criteria and the consequent reduction of deaths related to acute GVHD were the main reasons for the improvement of survival observed in patients grafted after 1992.

Pharmacology of desmin (low molecular weight dermatan sulphate) in healthy volunteers following intravenous bolus administration of different dosages (200, 400, 800 mg)

Eight healthy volunteers (6 males, 2 females, mean age 31.6 yrs), were administered--on three separate days--200, 400 and 800 mg of a new low molecular weight Dermatan sulphate (Desmin), given as a single i.v. bolus (2 min.) injection. Before each administration and 10, 20, 30 min., 1, 2, 4, 8, 12, 24 hours after, blood samples were drawn and the following coagulative assays performed: aPTT (activated Partial Thromboplastin Time), TT (Thrombin Time), anti Xa (Xa Factor inhibition), Heptest, Stachrom D.S.. Furthermore, a kinetic analysis was performed on the activity curves calculated on the Heptest and Stachrom data. Plasma peak values and half lives of the parameters checked showed a clear dose-effect relationship. aPTT and TT showed very short-lasting variations and the inhibition of Factor Xa was moderate, but significant. The most evident and specific effects of Desmin were those on Heptest and Stachrom D.S.: both tests were influenced in a clear-cut and dose-dependent way, mainly as a consequence of the action of Desmin on HCII, with partially different kinetic patterns. A series of in vitro experiments proved an anti Xa effect of Desmin, mediated by antithrombin III, well above the possible interference of the small (< 1%) heparin contaminants in Desmin. An even more marked anti Xa activity was seen in the in vivo study, an observation so far unrecognized for this type of drug: some possible interpretations of this fact are discussed.

Desmin 370, a low molecular weight dermatan sulfate, reduces the weight of preformed thrombi in rats made afibrinogenemic by ancrod

Desmin 370 (D370), a low molecular weight dermatan sulfate, has been shown to induce a marked reduction of the weight of preformed venous thrombi in rats and rabbits by mechanisms that appeared largely independent of inhibition of thrombus accretion. In order to provide further support for such a mechanism, we exploited the defibrinating capacity of ancrod to obtain a thrombosis model characterized by the lack of thrombus growth and thus sensitive only to agents promoting thrombus lysis. Thrombus formation in anesthetized rats was induced by vena cava ligature. Injection of ancrod (5 U/kg) 5 h after induction of venous stasis caused a more than 95% reduction in plasma fibrinogen and prevented thrombus accretion as indicated by the lack of thrombus weight increase during the 3 h experimental period (12.2 +/- 0.6 vs 14.5 +/- 1 as compared to 12.6 +/- 0.6 vs 19.6 +/- 0.8, p < 0.01, in control rats) and by the almost complete (> 90%) inhibition of 125I-fibrin(ogen) binding to thrombi. Moreover, when ancrod was given 1 h before vena cava ligature, no thrombi were formed within 2 h whereas at the same time interval visible thrombi were present in all control rats. Administration of D370 (10 mg/kg) to thrombus bearing rats, 1 h after induction of afibrinogenemia, resulted in a significant reduction in thrombus weight (43% after 2 h, p < 0.01) which was only slightly lower than that recorded in normofibrinogenemic rats (54%). Enhancement of plasma fibrinolytic activity by ancrod had no influence on thrombus lysis and was not all affected by administration of D370.(ABSTRACT TRUNCATED AT 250 WORDS)

The HLA class I-CML association revisited taking into account the two forms of gene fusion in the Philadelphia chromosome. A multicenter study

CML patients possess either a b3-a2 or a b2-a2 fusion between the BCR and ABL genes. Depending on the type of fusion, two different series of non-self potentially immunogenic peptides may be produced. If they are presented by HLA class I molecules and recognized by cytotoxic CD8 lymphocytes, individuals could be more susceptible or resistant to leukemic cells bearing one or the other form of fusion according to their HLA class I phenotype. To test this point, the frequencies of HLA-A and HLA-B alleles were compared between b3-a2 and the b2-a2 CML patients. In essence, no difference was found whose significance could withstand correction for multiple comparisons.