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FETAL TISSUE SAMPLING FOR DIAGNOSIS OF GENETIC DISORDERS CHORIONIC VILLOUS SAMPLING

FETAL TISSUE SAMPLING FOR DIAGNOSIS OF GENETIC DISORDERS CHORIONIC VILLOUS SAMPLING “A PERSONAL APPROACH” DR. RAJU SAHETYA M.D. ; D.G.O. ; D.F.P. ; F.C.P.S., F.I.C.O.G. OBSTETRICIAN & GYNAECOLOGIST PUSHPA MATERNITY HOME BOMBAY - INDIA. CHORIONIC VILLUS SAMPLING IN PRENATAL DIAGNOSIS

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FETAL TISSUE SAMPLING FOR DIAGNOSIS OF GENETIC DISORDERS CHORIONIC VILLOUS SAMPLING

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  1. FETAL TISSUE SAMPLING FOR DIAGNOSIS OF GENETIC DISORDERS CHORIONIC VILLOUS SAMPLING “A PERSONAL APPROACH” DR. RAJU SAHETYA M.D. ; D.G.O. ; D.F.P. ; F.C.P.S., F.I.C.O.G. OBSTETRICIAN & GYNAECOLOGIST PUSHPA MATERNITY HOME BOMBAY - INDIA

  2. CHORIONIC VILLUS SAMPLING IN PRENATAL DIAGNOSIS SAFETY & UTILIZATION DIFFICULTIES NCOUNTERED DR. RAJU SAHETYA M.D. ; D.G.O. ; D.F.P. ; F.C.P.S., F.I.C.O.G. OBSTETRICIAN & GYNAECOLOGIST PUSHPA MATERNITY HOME BOMBAY - INDIA

  3. Historical perspective in prenatal diagnosis • Modern era in 1952 by Bevus – technique of amniocentesis • Liley in 1961 – severity of erythroblastosis bilirubin level • IN 1966 – fetal cells from amniotic fluid cultured & karyotyped • In 1966 Hahnemann fetal chorionic villi T.V. by hysteroscope

  4. Historical Perspective in prenatal diagnosis (cont) • In 1970, Chinese workers blind aspiration of chorionic villi for fetal sex • In 1982, Kazy et al., - role of ultrasonography in successful CVS • In 1985, Brambati et al., rapid uncultured villi – Trisomy 21 at 11 week • Milan group able to minimize maternal cell contamination

  5. Diagnostic techniques for the 1st trimester • Pre-implantation embryo biopsy • Fetal cells isolated from maternal blood • Coelocentesis • Chorionic villous sampling • Ultrasonography

  6. Diagnostic techniques in the 2nd trimester • Late chorionic villous sampling • Amniocentesis • Maternal biochemical analysis • Ultrasonography • Fetal blood sampling

  7. Introduction • Chorionic Villus Sampling • Well established in prenatal diagnosis • Villi have same genetic constitution • Reflects chromosomal , biochemical & DNA • CVS as alternative to amniocentesis • Safe, reliable, widespread application • Multicentric study – sampling success 98%

  8. Indications for CVS in our multicentric study • A. Increased risk for Chromosome anomalies • 1.Advanced maternal age > 35 years • 2.Previous aneuploid offspring • 3.Parental balanced structural rearrangement • a. Reciprocal translocation • b. Robertsonian translocation • c. Inversions • 4.Maternal Abnormal serum screening • 5.Ultrasound diagnosis of anomalies • a. Major malformations • b. Minor anomalies • B. Previous offspring with NTD • C. Parents carriers of Mendelian traits • D. X-Linked Recessive Didorders

  9. Utilization of CVS • Rapid Karyotyping – when fetal blood sampling unavailable • Excellent source of fetal DNA – for prenatal diagnosis • Cloning of genes & to develop DNA probes • Enzyme expression – to identify inborn errors of metabolism

  10. PATIENT EVALUATION • GENETIC COUNSELLING • INDICATION FOR REFERAL REVIEWED • ALTERNATIVE PROCEDURES DISCUSSED • RISKS, COMPLICATIONS AND ADVANTAGES • TESTING VERSUS NO TESTING • INFORMED WRITTEN CONSENT CLINICAL EVALUATION • OBSTETRIC HISTORY • GENITAL INFECTIONS • BLEEDING IN CURRENT PREGNANCY

  11. PATIENT EVALUATION • ULTRASOUND EVALUATION • FETAL VIABILITY • GESTATIONAL AGE • CHORION FRONDOSUM • SUB-CHORIONIC BLEEDING • UTERO-CERVICAL RELATION • MULTIPLE GESTATION • PROCEDURE ORIENTATION

  12. PROCEDURE RELATEDANATOMY & EMBRYOLOGY • GESTATION SAC DOES NOT FILL THE UTERUS • CHORIONIC MEMBRANE SURROUNDS AMNIOTIC CAVITY • EXTAEMBRYONIC COELOM • CHORION LAEVE & CHORION FRONDOSUM • VILLI FLOAT AND LOOSELY ANCHORED • FRONDOSUM VILLI MITOTICALLY ACTIVE

  13. TECHNIQUES OF CHORIONIC VILLUS • SAMPLING 9 TO 11 WKS • TRANSCERVICAL -CHORIONIC VILLUS SAMPLING • T.C. - CVS 80 % IN OUR SERIES • TRANSABDOMINAL - CHORIONIC VILLUS SAMPLING • T.A. - • THE SELECTION OF THE ROUTE OF VCS AT THE DISCRETION • OF THE OPERATOR AND DEPENDS ON : • LOCATION OF CHORION FRONDOSUM • POSITION OF UTERUS AND BLADDER • PRESENCE OF UTERINE OR CERVICAL ABNORMALITIES • PATIENTS CO-OPERATION

  14. DEVICES USED IN C V S • PERSONAL EXPERIENCE • T.C. - CVS • STAINLESS STEEL RIGID / MALLEABLE • OLIVE TIP, GAUGE 16, LENGTH 20 TO 22 cms • 10CC DISPOSABLE SYRINGE • T.A. - CVS • LONG SPINAL NEEDLE,GAUGE 20/18, • LENGTH 10 TO 16 cms • 10CC SYRINGE / MECHANICAL SUCTION • WITH COLLECTING BOTTLE

  15. DEVICES USED IN CVS PERSONAL EXPERIENCE COMMON TO BOTH TRANSPORT CULTURE BOTTLE, PETRIDISH, LAB SUITABLE MEDIUM, VERTICAL TORCH / DISSECTING MICROSCOPE, PICK UP FORCE CANNULA ECONOMICAL, REUSABLE, EASY AUTOCLAVABLE, CLEANSED WITH SODIUM HYPO CHLORIDE MALLEABLE TO ALL SHAPES, OLIVE TIP ENABLES GOOD IMAGING

  16. TECHNIQUE TRANSCERVICAL CHRONIC VILLUS SAMPLING • ULTRASOUND EVALUTION • ASEPTIC PRECAUTIONS • PREFORMED CANNULA • ULTRASOUND GUIDANCE • NEGATIVE SUCTION • “TO & FRO” MOVEMENTS • OBSTETRICAN-SONOLOGIST • CO-ORDINATION

  17. Technique – Transabdominal Chorionic Villus Sampling • Ultrasound evaluation • Aseptic precautions • Ultrasound guided free hand technique • “Back & Forth” movements • Lower fetal loss by 0.5% • Reduced incidence of immediate bleeding

  18. CHORIONIC VILLUS SAMPLINGIN TWIN PREGNANCY • SPECIFIC COUNCELING • SEPARATE SETS OF DEVICES • DIFFERENT ROUTES • LIMIT ASPIRATION SITES • DIANOSTIC ERRORS • SELECTIVE TERMINATION • VANISHING TWIN

  19. ASSESMENT OF VILLI QUALITY • DISTINCTIVE FROND LIKE APPEARANCE • BUD-LIKE PROJECTIONS • BLOOD VESSELS COURSING ALONG THE • SURFACE • QUANTITY - 15 TO 20 mgs. WET, WEIGHT

  20. CVS - SAFETY • MATERNAL • REFERRAL INDICATION REVIEWED. • PATIENT EVALUATION • PREVIOUS PREGNANCY WASTAGE. • BLEEDING IN PRESENT PREGNANCY • INFECTIONS INVESTIGATE & TREAT • Rh SENSITIZATION--INCREASED RISK • RISE IN ALPHA-FETO PROTIENS

  21. CVS - SAFETY • FETUS • GESTATIONAL AGE CO- RELATION WITH USG. • TO RULE OUT DISCREPANCY • MULTIPLE GESTATION - RISKS INCREASES • SERIAL SCANS--BEFORE & AFTER PROCEDURE • MINIMISE VASCULAR INSULT • FOLLOW UP MID-TRIMESTER SCAN & ALPHA-FETO PROTIENS

  22. DIFFICULTIES ENCOUNTEREDDUE TO CERVICAL FACTORS • DECREASED CANNULA MANEUVERABILITY • LONG CX, PIN POINT STENOSED • BLEEDING AND INFECTIONS

  23. DIFFICULTIES ENCOUNTEREDDUE TO UTERINE FACTORS • POSITIONS • DEVIATION • CONTRACTIONS • SCARS & GROWTHS

  24. DIFFICULTIES ENCOUNTERED DUE TO CHORIONIC FRONDOSUM • LOCATION • LOW LYING • THICKNESS • SUB CHORIONIC BLEEDING HEMATOMA

  25. DIFFICULTIES ENCOUNTEREDDUE TO MATERNAL BLADDER • FULL BLADDER • ACCESS TO CX, HIGH REACH CHORION, MOBILITY OF UTERUS, DISCOMFORT. INSUFFICIENT BLADDER • POOR IMAGING & GUIDANCE, CERVICO-UTERINE ANGLE

  26. DIFFICULTIES ENCOUNTERED • PERSONAL EXPERIENCE -10 YRS. • IN T.A. - CVS • DISCOMFORT • MYOMAS • POSTERIOR LOCATION • BOWELS INTERVENING • MECHANICAL SUCTION • OBESITY • PREVIOUS SCARS

  27. PREGNANCY OUTCOME IN 5200 CASES • NORMAL LIVE BIRTHS 4800 • NEONATAL DEATHS 11 • SPONTANEOUS ABORTIONS 63 • PREMATURE DELIVERIES 22 • STILL BIRTHS 13 • IUFD 3 • ABNORMAL KARYOTYPE 132 • DEVELOPMENTAL DEFECTS 13 • LOST TO FOLLOW UP 143

  28. PREGNANCY OUTCOME IN 5200 CASES • DEVELOPMENTAL DEFECTS REPORTED • LIMB DEFECTS 3 • ENENCEPHALY 2 • OLIGOHYDRAMINIOS 6 • HYDROCEPHALUS 2

  29. RISK WITH CHORIONIC VILLUS SAMPLING • FETAL LOSS • INTRAUTERINE INFECTIONS • PERFORATION OF AMNIOTIC SAC • MID-TRIMESTER OLIGOHYDRAMNIOS • FETAL GROWTH AND DEVELOPMENT • MATERNAL CELL CONTAMINATION

  30. RISK WITH CHORIONIC VILLUS SAMPLING • CVS & LIMB ABNORMALITY • CVS PRIOR TO 8.6 WEEKS GESTATION • VASCULAR INSULT • INCOMPLETE MORPHOGENESIS • DISRUPTS NORMAL EMBRYO

  31. PATIENT’S ACCEPTANCE • SHORTER WAITING • PRIVACY • COMFORT • ADEQUATE COUNSELLING • WELL INFORMED PROCEDURE

  32. CONCLUSION - I • CHORIONIC VILLUS SAMPLING HAVE PROVED • TO BE REASONABLY SAFE AND RELIABLE • TECHNIQUE WITH WIDESPREAD APPLICATIONS • AND A HIGH DEGREEE OF ACCEPTANCE AMONG • WOMEN UNDERGOING PROCEDURE • FETAL LOSS RISK HAS BEEN DEMONTRATED • AS LOW ASAMNIOCENTESIS • NO ADVERSE EFFECTS WERE FOUND ON • FETAL GROWTH AND DEVELOPMENET IF CVS • PERFORMED BETWEEN 9 & 11 WEEKS GESTATIONS

  33. CONCLUSION - II • SELECTION BETWEEN T.C.-CVS / T.A.-CVS IS AT THE • THE DISCRETION OF THE OPERATOR AND DEPENDS ON • LOCATION OF CHORION, POSITION OF UTERUS, • PATIENTS CO-OPERATION. • OBSTETRICIAN - SONOLOGIST CO-ORDINATION IS OF • UTMOST IMPORTANCE FOR GOOD SAMPLING • WITH ADVANCES IN DAN TECHNOLOGY, ACURATE, • SAME DAY RESULTS, FOR PRENATAL DIAGNOSIS • BY CVS WITHOUT THE NEED FOR CULTURE IS POSSIBLE

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