CONTEXTO(S). En todo evento comunicativo, la relación de la textura discursiva con el contexto que lo envuelve es fundamental para comprender su sentido y

Nine studies compared duplex ultrasound with hand-held Doppler.

9.2.4.1 Patients

The patient population across the studies was predominantly primary, uncomplicated varicose veins.

Only three out of ten studies reported the CEAP classification of their patients. The CEAP classification illustrates a mild severity of the disease in most cases:

• Rautio et al. (2002b)¹⁴¹:all 62 limbs were CEAP 2 or 3;

• In a second study by the same author: 126 out of 137 limbs were CEAP 2 or 3¹⁴⁰;

• Kent and Weston (1998)¹³⁹ had only 10% of patients with a CEAP classification greater than three.

Patient numbers ranged between 37 and 188, with the exception of one larger study with 943 patients from the Campbell et al trial¹³⁵. The conclusions of four studies are based on tests performed on 100 or less limbs 48 136 138-143.

9.2.4.2 Outcomes

Of the ten studies, seven studies 48 136 139-143 reported on both diagnostic accuracy (location and extent of reflux) and clinically relevant outcomes (treatment plan or unnecessary treatment).

One study¹³⁷ reported on diagnostic accuracy only (location and extent of reflux).

The two last studies did not report on diagnostic accuracy outcomes ^{135 138}.

• Kambal et al. 2007¹³⁸ focused on the preoperative marking of the saphenopopliteal junction (SPJ) prior to surgery by comparing the accuracy of HHD with duplex. The outcome in this study was the distance in millimetres between the SPJ site located by HHD and the SPJ site located by duplex, with distances greater than ten millimetres deemed not acceptable for surgical accuracy.

• Campbell et al. 2005¹³⁵ reported on whether clinicians had requested a duplex scan and the extent of missed reflux by HHD.

9.2.4.3 Diagnostic accuracy of hand-held Doppler versus Duplex ultrasound Diagnostic accuracy at the saphenofemoral junction

Diagnostic accuracy (location and extent of reflux) of the saphenofemoral junction (SFJ) was reported in six of the nine HHD vs duplex studies 136 139-143. Overall, the sensitivity and specificity of HHD compared with duplex in the assessment of reflux in the great saphenous vein (GSV) was high.

In four studies with patient populations largely consisting of patients with primary, uncomplicated varicoses, the sensitivity ranged from 95% to 71.2% 136 139 142 143. Lower sensitivity was reported in the studies conducted by Rautio et al. (2002a and 2002b) 64% to 56%^{140 141}

Specificity was between 100% and 91% except in the study from Wills et al (70.9%) ¹³⁶

139-143.

The likelihood ratio value indicates the value of the test for increasing certainty about a positive diagnosis¹⁴⁴. The likelihood ratio of a positive test ranged from 95 in the Darke study¹³⁶ to 2.44 in the Wills study¹⁴³. These results show a high probability of a true positive reflecting the sensitivity results reported above. Correspondingly, the likelihood ratio of a negative test ranged from low values of 0.05 and 0.07 in the Darke¹³⁶ and Kent studies¹³⁹ to higher values 0.40 and 0.45 in the Rautio¹¹² and Wills¹⁴³ studies.

Diagnostic accuracy at the saphenopopliteal junction

Diagnostic accuracy in the small saphenous vein (SSV) was assessed in six studies ^{136 137}

139 140 142 143. The sensitivity and specificity of HHD at the saphenopopliteal junction (SPJ) were lower than at the SFJ. A prospective study by Daher et al. (2001) compared the diagnostic accuracy of HHD with duplex specifically at the SPJ. One hundred and seventy-one limbs were evaluated: 116 limbs showed reflux at SPJ using HHD, however only 73 of these were true positives on duplex, reporting a sensitivity of 92% and a specificity of 53% (PPV=62%, NPV+89%, accuracy = 70%) at the SPJ¹³⁷. The likelihood ratio of a positive test in this study was calculated to be 1.96 which shows the likelihood of a patient being accurately diagnosed with SPJ incompetence is approximately twice that of a negative result. This was the lowest likelihood ratio positive calculated for the SPJ studies and is a reflection of the lower specificity reported in this study.

In a smaller study, Darke et al. (2001) compared the diagnostic accuracy of continuous wave doppler with duplex in 21 limbs with SSV incompetence. They reported a sensitivity of 90% and a specificity of 93%¹³⁶. The likelihood ratio positive was also high (12.85) and the likelihood ratio negative low (0.1).

A lower accuracy was detected by Kent and Weston (1998) who reported a sensitivity of 82% and sensitivity of 80% at the SPJ in primary varicose veins (108 limbs)¹³⁹, although the likelihood ratio of a positive test was calculated to be 4.1 indicating the likelihood of a patient having SPJ incompetence is approximately four times that of a negative result.

However, lower rates of accuracy were detected in the other three studies that reported SPJ findings. The sensitivity ranged from 56% in the Salaman et al. (1995)¹⁴² study to 36.1% in Wills et al. (1998)¹⁴³ and 23% in the Rautio et al. (2002a)¹⁴⁰ study.

Specificity was greater than 80% in all studies except Daher et al. (2001) which reported a lower specificity of 53%¹³⁷. The calculated likelihood ratio positive values in these three studies ranged from 4.6 to 5.75 and the likelihood ratio negative values between 0.49 to 0.8 140 142 143.

Overall, the ranges reported for diagnostic accuracy at the saphenopopliteal junction were large: sensitivity reported in six studies ranged from 92% to 23% and the specificity from 96% to 53% 136 137 139 140 142 143.

9.2.4.4 Summary: diagnostic accuracy of hand-held Doppler

The table below summarises the results from the eight studies evaluating the accuracy of HHD at the SFJ and SPJ.

Summary of sensitivity and specificity results from hand-held Doppler versus duplex

Study Study population Sensitivit

y SFJ Specificity

SFJ Sensitivity

SPJ Specificit

Patients requiring SPJ scan

LRP=95 LRN=0.05 LRP=12.85 LRN=0.1 Kambal 2007 ¹³⁸

Patients with clinically suspected SPJ reflux

CEAP: NR NR NR NR NR

Kent and Weston 1998 ¹³⁹

Primary uncomplicated varicose veins; CEAP 1 : 0.9%

CEAP 2: 89%

CEAP 4: 8.3%

CEAP 6: 1.8%

93% 91% 82% 80%

LRP=10.3 LRN=0.07 LRP=4.1 LRN=0.2

Rautio 2002a ¹⁴⁰

Primary varicose veins CEAP 1 : 4%

CEAP 2: 47%

CEAP 3: 42%

CEAP 4: 8%

56% 97% 23% 96%

LRP=18.6 LRN=0.45 LRP=5.75 LRN=0.8

Rautio 2002b ¹⁴¹

Primary

Salaman 1995 ¹⁴²

Primary uncomplicated varicose veins 82%, secondary 18%

CEAP:NR

92% 94% 56% 89%

LRP=15.3 LRN=0.08 LRP=5.1 LRN=0.49

Wills 1998 ¹⁴³

Primary uncomplicated varicose veins 95%, secondary 5%

CEAP:NR

71.2% 70.9% 36.1% 92.1%

LRP=2.44 LRN=0.40 LRP=4.6 LRN=0.69

LRP= Likelihood ratio positive; LRN=likelihood ratio negative Τ – These studies did not report on diagnostic accuracy outcomes

Diagnostic accuracy of hand-held Doppler

• Overall, the sensitivity and specificity of hand-held Doppler compared with duplex ultrasound in the assessment of reflux in the great saphenous vein was found to be high;

• The accuracy of hand-held Doppler in the small saphenous vein, particularly the popliteal fossa, was found to be less reliable as was the assessment for anatomical deformities.

9.2.5 Clinical Consequences of the findings: hand-held Doppler versus Colour