Table 12.

—[Section 2.10] Summary of Findings: Systemic Lysis vs No Systemic Lysis for Extensive Acute DVT of the Leg¹³⁸

Outcomes	No. of Participants (Studies), Follow-up	Quality of the Evidence (GRADE)	Relative Effect (95% CI)	Anticipated Absolute Effects
				Risk With No Systemic Lysis	Risk Difference With Systemic Lysis (95% CI)
Mortality	688 (5 studies), 3 moa	Lowb-e due to imprecision	RR 0.86 (0.27-2.68)	21 per 1,000	3 fewer per 1,000 (from 16 fewer to 36 more)
Nonfatal recurrent VTE	687 (3 studies), 3 mof	Lowd,e,g due to imprecision	RR 1.28 (0.25-6.68)	48 per 1,000h	13 more per 1,000 (from 36 fewer to 273 more)
Nonfatal major bleeding	688 (10 studies), 3 mof	Moderatec,d,i due to imprecision	RR 1.84 (0.94-3.59)	29 per 1,000h,j	24 more per 1,000 (from 2 fewer to 75 more)
PTS	678 (2 studies), 2 yk	Lowd,e,l,m due to risk of bias and imprecision	RR 0.71 (0.49-1.04)	588 per 1,000n	171 fewer per 1,000 (from 300 fewer to 24 more)o
QOL not measured	…	…	…	…	…

The basis for the assumed risk (eg, the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). Working group grades of evidence are as follow: High quality, further research is very unlikely to change our confidence in the estimate of effect; moderate quality, further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate; low quality, further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate; very-low quality, we are very uncertain about the estimate. See Table 1, 3, and 10 legends for expansion of abbreviations.

^aRange of follow-up in included studies, 1 to 72 mo.

^bAllocation was concealed in three of five studies. Follow-up inadequate in one of five studies (Common et al¹³⁹). Excluding this study from the analysis does not change the effect estimate. All studies had blinded outcome assessors. None of the studies used a placebo control.

^cThe population of one study (Schulman et al¹³¹) comprised patients with calf vein thrombosis.

^dInterventions varied across studies with regard to agent (eg, tissue plasminogen activator, streptokinase, urokinase), dose, use of the pedal vein administration, duration of treatment, and concomitant drugs (eg, steroids). However, we did not downgrade for indirectness given that there was no standard regimen and all analyses showed no heterogeneity in results.

^eCI included both no effect and a potentially significant effect.

^fRange of follow-up in included studies, 1 to 30 d.

^gAllocation was concealed in two of three studies. Follow-up adequate in all studies. All studies had blinded outcome assessors. None of the studies used a placebo control.

^hBaseline risks for nonfatal recurrent VTE and for major bleeding derived from Douketis et al.¹⁰⁸

ⁱAllocation was concealed in seven of 10 studies. Follow-up inadequate in one of 10 studies (Common et al¹³⁹). Excluding this study from the analysis does not affect the effect estimate. All studies had blinded outcome assessors. Two studies used placebo (Turpie et al¹³⁵ and Verhaeghe et al¹³⁶).

^jOnly 4% of all major bleeding events were intracranial bleeds.

^kRange of follow-up in included studies, 1 to 6 y.

^lAllocation was concealed in two of two studies. Follow-up adequate in both studies. Both studies had blinded outcome assessors. Neither study used placebo control.

^mNo use of a standardized validated tool reported.

ⁿThis estimate is based on the findings of the VETO study.¹⁰² This probably underestimates PTS baseline risk, given that overall, 52% of patients reported the current use of compression stockings during study follow-up.

^oSevere PTS: Assuming the same RR of 0.71 and a baseline risk of 13.8%,¹⁰² the absolute reduction is 40 fewer severe PTS per 1,000 (from 70 fewer to 6 more) over 2 y.